Clean visual style: move to Light, add Material support, change Drawables (progress, icons).

This code alters the visual style moving the APP to a Light theme.
Parents of the theme are either Theme.Holo.Light or Theme.Material.Light
depending on which API we start the APK from. Needs SDK 21 to build.

Other than the visual changes, this commit changes:
 - name of the APP to 'Browser'
 - animations and sequencing of the Tab switcher in {nav/anim}_screen
 - removal of the warning icon from the Exit dialog
 - change of the favicon appearance (removal of the double border)

Vast amount of unused resources are removed from the APK. Just XHDPI
drawables have been synthesized for now, and the Primary color was
used for the icons and is accessible in R.color.Primary.

Change-Id: If75cc051c5d4015383e96066cdb6507484e625d8
diff --git a/res/drawable/ic_action_tabswitcher.xml b/res/drawable/ic_action_tabswitcher.xml
new file mode 100644
index 0000000..bc927a6
--- /dev/null
+++ b/res/drawable/ic_action_tabswitcher.xml
@@ -0,0 +1,44 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!--
+     Copyright (c) 2014, The Linux Foundation. All rights reserved.
+
+     Redistribution and use in source and binary forms, with or without
+     modification, are permitted provided that the following conditions are
+     met:
+         * Redistributions of source code must retain the above copyright
+           notice, this list of conditions and the following disclaimer.
+         * Redistributions in binary form must reproduce the above
+           copyright notice, this list of conditions and the following
+           disclaimer in the documentation and/or other materials provided
+           with the distribution.
+         * Neither the name of The Linux Foundation nor the names of its
+           contributors may be used to endorse or promote products derived
+           from this software without specific prior written permission.
+
+     THIS SOFTWARE IS PROVIDED "AS IS" AND ANY EXPRESS OR IMPLIED
+     WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+     MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT
+     ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS
+     BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+     CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+     SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
+     BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
+     WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
+     OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN
+     IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+-->
+
+<selector xmlns:android="http://schemas.android.com/apk/res/android">
+
+    <item android:state_enabled="true" android:state_pressed="true"
+        android:drawable="@drawable/ic_action_tabswitcher_active" />
+
+    <item android:state_enabled="true" android:state_selected="true"
+        android:drawable="@drawable/ic_action_tabswitcher_active" />
+
+    <item android:state_enabled="false"
+        android:drawable="@drawable/ic_action_tabswitcher_disabled" />
+
+    <item android:drawable="@drawable/ic_action_tabswitcher_normal" />
+
+</selector>