implemented snackbar - UNDO on closing tab

https://sourceforge.net/p/kiwix/feature-requests/232/

build.gradle

@@ -23,6 +23,7 @@ dependencies {
   compile 'com.android.support:support-v4:22.2.0'
   compile files("$buildDir/native-libs/native-libs.jar")
   compile 'com.yahoo.squidb:squidb:2.0.0'
+  compile 'com.android.support:design:22.2.0'
   compile 'com.yahoo.squidb:squidb-annotations:2.0.0'
   apt 'com.yahoo.squidb:squidb-processor:2.0.0'
   // compile fileTree(dir: '.', include: 'content-libs.jar') // DO NOT REMOVE !!

res/layout/main.xml

@@ -2,7 +2,8 @@
 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
     android:layout_width="match_parent"
     android:layout_height="match_parent"
-    android:orientation="vertical">
+    android:orientation="vertical"
+    android:id="@+id/linearlayout_main">
 
   <include layout="@layout/toolbar"/>
 

res/values/colors.xml

@@ -8,7 +8,7 @@
   <color name="secondary_text">#727272</color>
   <color name="icons">#212121</color>
   <color name="divider">#B6B6B6</color>
-
+  <color name="white_undo">#FAFAFA</color>
   <color name="gray_list_bg">#0d000000</color>
   <color name="drawer_background">#ffffff</color>
   <color name="selected_light">#0F000000</color>