Remove custom clang and osx image version

.travis.yml

@@ -116,28 +116,9 @@ matrix:
       env:
         - CC=clang
         - CXX=clang++
-    # clang 3.8
-    - compiler: clang
-      os: linux
-      env:
-        - CC=clang
-        - CXX=clang++
-        - LLVM_VERSION=3.8.0
-        - LLVM_ARCHIVE_PATH=$HOME/clang+llvm.tar.xz
-        - CPPFLAGS="-I $HOME/clang-$LLVM_VERSION/include/c++/v1"
-        - CXXFLAGS=-lc++
-        - PATH=$HOME/clang-$LLVM_VERSION/bin:$PATH
-        - LD_LIBRARY_PATH=$HOME/clang-$LLVM_VERSION/lib:$LD_LIBRARY_PATH
-      before_install:
-        - wget http://llvm.org/releases/$LLVM_VERSION/clang+llvm-$LLVM_VERSION-x86_64-linux-gnu-ubuntu-14.04.tar.xz -O $LLVM_ARCHIVE_PATH
-        - mkdir $HOME/clang-$LLVM_VERSION
-        - tar xf $LLVM_ARCHIVE_PATH -C $HOME/clang-$LLVM_VERSION --strip-components 1
     # os x
     - compiler: clang
       os: osx
-      osx_image: xcode8
-      #install:
-      #  - brew install cmake
       env:
         - CC=clang
         - CXX=clang