diff --git a/.travis.yml b/.travis.yml
index 158a37d..60d4617 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -8,4 +8,4 @@ before_install:
   - sudo apt-get update -qq
   - sudo apt-get install -qq cmake libsdl2-dev libsdl2-image-dev g++-4.8
   - if [ "$CXX" = "g++" ]; then export CXX="g++-4.8" CC="gcc-4.8"; fi
-script: cmake . -DRUN_GUI_TESTS=OFF -DCMAKE_INSTALL_PREFIX=`pwd`/_prefix -DSDL2PP_WITH_WERROR=YES && make && make test && make install
+script: cmake . -DSDL2PP_ENABLE_GUI_TEST=OFF -DCMAKE_INSTALL_PREFIX=`pwd`/_prefix -DSDL2PP_WITH_WERROR=YES && make && make test && make install
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 2558c16..5d3fe76 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -5,6 +5,12 @@ CMAKE_MINIMUM_REQUIRED(VERSION 2.8)
 
 SET(CMAKE_MODULE_PATH ${PROJECT_SOURCE_DIR}/cmake)
 
+SET(SDL2PP_MAJOR_VERSION 0)
+SET(SDL2PP_MINOR_VERSION 4)
+SET(SDL2PP_PATCH_VERSION 0)
+
+SET(SDL2PP_VERSION "${SDL2PP_MAJOR_VERSION}.${SDL2PP_MINOR_VERSION}.${SDL2PP_PATCH_VERSION}")
+
 # there are functions present on wiki, but not yet in stable SDL2 releases;
 # we hide these under following options
 OPTION(SDL2PP_WITH_2_0_4 "Enable new functions available only in SDL2 2.0.4+" OFF)
@@ -37,6 +43,8 @@ ELSE(MSVC)
 	SET(WERROR_FLAG "-Werror")
 ENDIF(MSVC)
 
+LIST(REMOVE_DUPLICATES SDL2_ALL_INCLUDE_DIRS)
+
 INCLUDE_DIRECTORIES(BEFORE ${PROJECT_SOURCE_DIR})
 INCLUDE_DIRECTORIES(${SDL2_ALL_INCLUDE_DIRS})
 
@@ -94,15 +102,41 @@ IF(CMAKE_SOURCE_DIR STREQUAL PROJECT_SOURCE_DIR)
 	TARGET_LINK_LIBRARIES(SDL2pp ${SDL2_ALL_LIBRARIES})
 	SET_TARGET_PROPERTIES(SDL2pp PROPERTIES VERSION 1.0.0 SOVERSION 1)
 
-	# demos and tests
-	OPTION(RUN_GUI_TESTS "Run GUI tests (requires X11 display)" ON)
-	ENABLE_TESTING()
+	# examples and tests
+	OPTION(SDL2PP_WITH_EXAMPLES "Build examples" ON)
+	OPTION(SDL2PP_WITH_TESTS "Build tests" ON)
+	OPTION(SDL2PP_ENABLE_GUI_TEST "Enable GUI test (requires X11 display)" ON)
 
-	ADD_SUBDIRECTORY(demos)
-	ADD_SUBDIRECTORY(tests)
+	IF(SDL2PP_WITH_EXAMPLES)
+		ADD_SUBDIRECTORY(examples)
+	ENDIF(SDL2PP_WITH_EXAMPLES)
 
+	IF(SDL2PP_WITH_TESTS)
+		ENABLE_TESTING()
+		ADD_SUBDIRECTORY(tests)
+	ENDIF(SDL2PP_WITH_TESTS)
+
+	# pkgconfig
+	SET(PKGCONFIGDIR lib/pkgconfig CACHE STRING "directory where to install pkg-config files")
+	IF(CMAKE_SYSTEM_NAME MATCHES "FreeBSD")
+		SET(PKGCONFIGDIR libdata/pkgconfig)
+	ENDIF(CMAKE_SYSTEM_NAME MATCHES "FreeBSD")
+
+	SET(SDL2_PKGCONFIG_CFLAGS "")
+	FOREACH(INCDIR IN LISTS SDL2_ALL_INCLUDE_DIRS)
+		SET(SDL2_PKGCONFIG_CFLAGS "${SDL2_PKGCONFIG_CFLAGS} -I${INCDIR}")
+	ENDFOREACH(INCDIR IN SDL2_ALL_INCLUDE_DIRS)
+
+	CONFIGURE_FILE(
+		sdl2pp.pc.in
+		sdl2pp.pc
+		@ONLY
+	)
+
+	# install
 	INSTALL(FILES ${LIBRARY_HEADERS} ${PROJECT_BINARY_DIR}/SDL2pp/Config.hh DESTINATION include/SDL2pp)
 	INSTALL(TARGETS SDL2pp LIBRARY DESTINATION lib)
+	INSTALL(FILES ${PROJECT_BINARY_DIR}/sdl2pp.pc DESTINATION ${PKGCONFIGDIR})
 ELSE(CMAKE_SOURCE_DIR STREQUAL PROJECT_SOURCE_DIR)
 	MESSAGE(STATUS "libSDL2pp bundled build")
 
diff --git a/README.md b/README.md
index 03e8ff3..6be47be 100644
--- a/README.md
+++ b/README.md
@@ -83,13 +83,34 @@ Dependencies:
 * SDL_image2 (optional)
 
 To build standalone version:
+
 ```cmake . && make```
 
+## Installation ##
+
+To install the library systemwide, run:
+
+```cmake . && make && make install```
+
+You can change installation prefix with CMAKE_INSTALL_PREFIX cmake
+variable:
+
+```cmake -DCMAKE_INSTALL_PREFIX=/usr/local . && make && make install```
+
+SDL2pp install pkg-config file, so it can be used with any build
+system which interacts with pkg-config, including CMake and GNU
+Autotools.
+
+SDL2pp is also already available from following package repositories:
+
+* [Arch Linux AUR](https://aur.archlinux.org/packages/sdl2pp-git/)
+* [FreeBSD ports](http://www.freshports.org/devel/sdl2pp/)
+
 ## Bundling ##
 
 The library is easy to integrate into other CMake-using projects
 (and as the library has no stable API yet, this way of using it is
-preferred).
+still recommended).
 
 Just place the library into dedicated directory in your project
 (for example, lib/SDL2pp) and add
@@ -111,7 +132,7 @@ ADD_EXECUTABLE(mytarget ...)
 TARGET_LINK_LIBRARIES(mytarget ${SDL2PP_LIBRARIES})
 ```
 
-if bundled, libSDL2pp does not build demos and becomes a static
+if bundled, libSDL2pp does not build examples and becomes a static
 library, providing required SDL2 includes/libs in the mentioned
 variables.
 
diff --git a/SDL2pp/AudioDevice.hh b/SDL2pp/AudioDevice.hh
index 40bfcf6..27eada6 100644
--- a/SDL2pp/AudioDevice.hh
+++ b/SDL2pp/AudioDevice.hh
@@ -135,9 +135,23 @@ public:
 		////////////////////////////////////////////////////////////
 		LockHandle& operator=(LockHandle&& other) noexcept;
 
-		// Deleted copy constructor and assignment
-		LockHandle(const LockHandle& other) = delete;
-		LockHandle& operator=(const LockHandle& other) = delete;
+		////////////////////////////////////////////////////////////
+		/// \brief Copy constructor
+		///
+		/// \param other SDL2pp::AudioDevice::LockHandle to copy data from
+		///
+		////////////////////////////////////////////////////////////
+		LockHandle(const LockHandle& other);
+
+		////////////////////////////////////////////////////////////
+		/// \brief Assignment operator
+		///
+		/// \param other SDL2pp::AudioDevice::LockHandle to copy data from
+		///
+		/// \returns Reference to self
+		///
+		////////////////////////////////////////////////////////////
+		LockHandle& operator=(const LockHandle& other);
 	};
 
 	typedef std::function<void(Uint8* stream, int len)> AudioCallback;
diff --git a/SDL2pp/AudioLock.cc b/SDL2pp/AudioLock.cc
index 55a1383..159c518 100644
--- a/SDL2pp/AudioLock.cc
+++ b/SDL2pp/AudioLock.cc
@@ -53,4 +53,21 @@ AudioDevice::LockHandle& AudioDevice::LockHandle::operator=(AudioDevice::LockHan
 	return *this;
 }
 
+AudioDevice::LockHandle::LockHandle(const AudioDevice::LockHandle& other) : device_(other.device_) {
+	SDL_LockAudioDevice(device_->device_id_);
+}
+
+AudioDevice::LockHandle& AudioDevice::LockHandle::operator=(const AudioDevice::LockHandle& other) {
+	if (&other == this)
+		return *this;
+
+	if (device_ != nullptr)
+		SDL_UnlockAudioDevice(device_->device_id_);
+
+	device_ = other.device_;
+	SDL_LockAudioDevice(device_->device_id_);
+
+	return *this;
+}
+
 }
diff --git a/SDL2pp/Config.hh.in b/SDL2pp/Config.hh.in
index edc4b9b..ac60ca8 100644
--- a/SDL2pp/Config.hh.in
+++ b/SDL2pp/Config.hh.in
@@ -22,6 +22,12 @@
 #ifndef SDL2PP_CONFIG_HH
 #define SDL2PP_CONFIG_HH
 
+#define SDL2PP_MAJOR_VERSION @SDL2PP_MAJOR_VERSION@
+#define SDL2PP_MINOR_VERSION @SDL2PP_MINOR_VERSION@
+#define SDL2PP_PATCH_VERSION @SDL2PP_PATCH_VERSION@
+
+#define SDL2PP_VERSION "@SDL2PP_VERSION@"
+
 #cmakedefine SDL2PP_WITH_IMAGE
 #cmakedefine SDL2PP_WITH_2_0_4
 
diff --git a/SDL2pp/Rect.cc b/SDL2pp/Rect.cc
index f27212a..2f7a5ab 100644
--- a/SDL2pp/Rect.cc
+++ b/SDL2pp/Rect.cc
@@ -137,4 +137,34 @@ bool Rect::Contains(const Point& point) const {
 	return !(point.GetX() < GetX() || point.GetY() < GetY() || point.GetX() > GetX2() || point.GetY() > GetY2());
 }
 
+Rect Rect::operator+(const Point& offset) const {
+	assert(!IsNull() && !offset.IsNull());
+
+	return Rect(rect_.x + offset.GetX(), rect_.y + offset.GetY(), rect_.w, rect_.h);
+}
+
+Rect& Rect::operator+=(const Point& offset) {
+	assert(!IsNull() && !offset.IsNull());
+
+	rect_.x += offset.GetX();
+	rect_.y += offset.GetY();
+
+	return *this;
+}
+
+Rect Rect::operator-(const Point& offset) const {
+	assert(!IsNull() && !offset.IsNull());
+
+	return Rect(rect_.x - offset.GetX(), rect_.y - offset.GetY(), rect_.w, rect_.h);
+}
+
+Rect& Rect::operator-=(const Point& offset) {
+	assert(!IsNull() && !offset.IsNull());
+
+	rect_.x -= offset.GetX();
+	rect_.y -= offset.GetY();
+
+	return *this;
+}
+
 }
diff --git a/SDL2pp/Rect.hh b/SDL2pp/Rect.hh
index e7f3af6..a8305c8 100644
--- a/SDL2pp/Rect.hh
+++ b/SDL2pp/Rect.hh
@@ -78,6 +78,12 @@ public:
 	void SetY2(int y2);
 
 	bool Contains(const Point& point) const;
+
+	Rect operator+(const Point& offset) const;
+	Rect& operator+=(const Point& offset);
+
+	Rect operator-(const Point& offset) const;
+	Rect& operator-=(const Point& offset);
 };
 
 }
diff --git a/SDL2pp/Texture.cc b/SDL2pp/Texture.cc
index 8e012b3..7180444 100644
--- a/SDL2pp/Texture.cc
+++ b/SDL2pp/Texture.cc
@@ -98,7 +98,7 @@ void Texture::SetColorMod(Uint8 r, Uint8 g, Uint8 b) {
 		throw Exception("SDL_SetTextureColorMod failed");
 }
 
-Texture::LockHandle Texture::Lock(const Rect& rect) {
+Texture::LockHandle Texture::Lock(const Rect& rect = Rect::Null()) {
 	return LockHandle(this, rect);
 }
 
diff --git a/demos/CMakeLists.txt b/examples/CMakeLists.txt
similarity index 100%
rename from demos/CMakeLists.txt
rename to examples/CMakeLists.txt
diff --git a/demos/audio_sine.cc b/examples/audio_sine.cc
similarity index 100%
rename from demos/audio_sine.cc
rename to examples/audio_sine.cc
diff --git a/demos/audio_wav.cc b/examples/audio_wav.cc
similarity index 100%
rename from demos/audio_wav.cc
rename to examples/audio_wav.cc
diff --git a/demos/image.cc b/examples/image.cc
similarity index 100%
rename from demos/image.cc
rename to examples/image.cc
diff --git a/demos/lines.cc b/examples/lines.cc
similarity index 100%
rename from demos/lines.cc
rename to examples/lines.cc
diff --git a/demos/rendertarget.cc b/examples/rendertarget.cc
similarity index 100%
rename from demos/rendertarget.cc
rename to examples/rendertarget.cc
diff --git a/demos/sprites.cc b/examples/sprites.cc
similarity index 100%
rename from demos/sprites.cc
rename to examples/sprites.cc
diff --git a/sdl2pp.pc.in b/sdl2pp.pc.in
new file mode 100644
index 0000000..7313e27
--- /dev/null
+++ b/sdl2pp.pc.in
@@ -0,0 +1,14 @@
+# libSDL2pp pkg-config source file
+
+prefix=@CMAKE_INSTALL_PREFIX@
+exec_prefix=${prefix}
+libdir=${exec_prefix}/lib
+includedir=${prefix}/include
+
+Name: sdl2pp
+Description: C++11 bindings/wrappers for SDL2.
+Version: @SDL2PP_VERSION@
+Requires:
+Conflicts:
+Libs: -L${libdir} -lSDL2pp
+Cflags: -I${includedir}@SDL2_PKGCONFIG_CFLAGS@
diff --git a/tests/CMakeLists.txt b/tests/CMakeLists.txt
index 1330632..aeb6025 100644
--- a/tests/CMakeLists.txt
+++ b/tests/CMakeLists.txt
@@ -30,7 +30,7 @@ ENDFOREACH(TEST ${TESTS})
 FOREACH(TEST ${GUI_TESTS})
 	ADD_EXECUTABLE(${TEST} ${TEST}.cc)
 	TARGET_LINK_LIBRARIES(${TEST} SDL2pp)
-	IF(RUN_GUI_TESTS)
+	IF(SDL2PP_ENABLE_GUI_TEST)
 		ADD_TEST(${TEST} ${TEST})
-	ENDIF(RUN_GUI_TESTS)
+	ENDIF(SDL2PP_ENABLE_GUI_TEST)
 ENDFOREACH(TEST ${TESTS})
diff --git a/tests/test_pointrect.cc b/tests/test_pointrect.cc
index 46653a0..3e3a3fb 100644
--- a/tests/test_pointrect.cc
+++ b/tests/test_pointrect.cc
@@ -173,4 +173,20 @@ BEGIN_TEST()
 		EXPECT_TRUE(!r.Contains(Point(15, 20)));
 		EXPECT_TRUE(!r.Contains(Point(10, 25)));
 	}
+
+	{
+		// Rect offset
+		Rect r(1, 2, 3, 4);
+
+		EXPECT_TRUE(r + Point(10, 20) == Rect(11, 22, 3, 4));
+		EXPECT_TRUE(r - Point(10, 20) == Rect(-9, -18, 3, 4));
+
+		r += Point(10, 20);
+
+		EXPECT_TRUE(r == Rect(11, 22, 3, 4));
+
+		r -= Point(20, 40);
+
+		EXPECT_TRUE(r == Rect(-9, -18, 3, 4));
+	}
 END_TEST()
diff --git a/tests/test_rwops.cc b/tests/test_rwops.cc
index b9b7275..dc3c120 100644
--- a/tests/test_rwops.cc
+++ b/tests/test_rwops.cc
@@ -24,19 +24,19 @@ BEGIN_TEST()
 
 		{
 			// Seeks
-			EXPECT_TRUE(rw.Seek(0, SEEK_SET) == 0);
+			EXPECT_TRUE(rw.Seek(0, RW_SEEK_SET) == 0);
 			EXPECT_TRUE(rw.Tell() == 0);
-			EXPECT_TRUE(rw.Seek(1, SEEK_SET) == 1);
+			EXPECT_TRUE(rw.Seek(1, RW_SEEK_SET) == 1);
 			EXPECT_TRUE(rw.Tell() == 1);
-			EXPECT_TRUE(rw.Seek(1, SEEK_CUR) == 2);
+			EXPECT_TRUE(rw.Seek(1, RW_SEEK_CUR) == 2);
 			EXPECT_TRUE(rw.Tell() == 2);
-			EXPECT_TRUE(rw.Seek(-1, SEEK_END) == 3);
+			EXPECT_TRUE(rw.Seek(-1, RW_SEEK_END) == 3);
 			EXPECT_TRUE(rw.Tell() == 3);
 		}
 
 		{
 			// Read via C++
-			EXPECT_TRUE(rw.Seek(0, SEEK_SET) == 0);
+			EXPECT_TRUE(rw.Seek(0, RW_SEEK_SET) == 0);
 
 			char buf[4] = {0};
 			EXPECT_TRUE(rw.Read(buf, 1, 4) == 4);
@@ -48,7 +48,7 @@ BEGIN_TEST()
 
 		{
 			// Read via C++
-			EXPECT_TRUE(rw.Seek(0, SEEK_SET) == 0);
+			EXPECT_TRUE(rw.Seek(0, RW_SEEK_SET) == 0);
 
 			char buf[4] = {0};
 			EXPECT_TRUE(rw.Read(buf, 4, 1) == 1);
@@ -60,7 +60,7 @@ BEGIN_TEST()
 
 		{
 			// Read via SDL
-			EXPECT_TRUE(rw.Seek(0, SEEK_SET) == 0);
+			EXPECT_TRUE(rw.Seek(0, RW_SEEK_SET) == 0);
 
 			char buf[4] = {0};
 			EXPECT_TRUE(SDL_RWread(rw.Get(), buf, 1, 4) == 4);
@@ -72,17 +72,17 @@ BEGIN_TEST()
 
 		{
 			// Overread
-			EXPECT_TRUE(rw.Seek(0, SEEK_SET) == 0);
+			EXPECT_TRUE(rw.Seek(0, RW_SEEK_SET) == 0);
 
 			char buf[6] = {0};
 			EXPECT_TRUE(SDL_RWread(rw.Get(), buf, 3, 2) == 1);
-			rw.Seek(0, SEEK_SET);
+			rw.Seek(0, RW_SEEK_SET);
 			EXPECT_TRUE(SDL_RWread(rw.Get(), buf, 2, 3) == 2);
 		}
 
 		{
 			// Write
-			EXPECT_TRUE(rw.Seek(0, SEEK_SET) == 0);
+			EXPECT_TRUE(rw.Seek(0, RW_SEEK_SET) == 0);
 
 			char buf[2] = {'1', '2'};
 			EXPECT_TRUE(rw.Write(buf, 1, 2) == 2);
@@ -98,7 +98,7 @@ BEGIN_TEST()
 		{
 			// Write past EOF
 			char buf[2] = {'x', 'y'};
-			EXPECT_TRUE(rw.Seek(100, SEEK_SET) == 100);
+			EXPECT_TRUE(rw.Seek(100, RW_SEEK_SET) == 100);
 
 			EXPECT_TRUE(rw.Write(buf, 1, 2) == 2);
 			EXPECT_TRUE(rw.Tell() == 102);
@@ -123,7 +123,7 @@ BEGIN_TEST()
 
 		{
 			// Read via C++
-			EXPECT_TRUE(rw.Seek(0, SEEK_SET) == 0);
+			EXPECT_TRUE(rw.Seek(0, RW_SEEK_SET) == 0);
 
 			char buf[4] = {0};
 			EXPECT_TRUE(rw.Read(buf, 1, 4) == 4);
@@ -152,7 +152,7 @@ BEGIN_TEST()
 			EXPECT_TRUE(rw.Write(buf, 1, 4) == 4);
 			EXPECT_TRUE(rw.Write(buf, 4, 1) == 1);
 
-			EXPECT_TRUE(rw.Seek(2, SEEK_SET) == 2);
+			EXPECT_TRUE(rw.Seek(2, RW_SEEK_SET) == 2);
 			EXPECT_TRUE(rw.Write(buf, 2, 2) == 2);
 
 			EXPECT_TRUE(vec.size() == 8);