Add new Android build and install scripts

Add new Android build and install scripts

This change adds new Android build and install scripts under
scripts/android. Key improvements over old ones are:

 * Build no longer relies on ant or 'android project' tools.

 * Native code build leverages scripts/build code which should fix
   incremental builds and improve compatibility.

 * Build script error reporting should be much better.

 * Final APK is now built incrementally which should enable much faster
   incremental builds once asset copy targets are fixed in main build.

This work required some changes to common code:

 * Android cross-compile toolchain is set up by including
   targets/android/ndk-r11.cmake before project() in the main
   CMakeLists.txt instead of using -DCMAKE_TOOLCHAIN_FILE. CMake native
   toolchain file support seems incredbly buggy and configuring
   toolchain in regular build files seems to be much more robust.

 * scripts/build/config.py now finds CMake automatically on OS X.

 * New HostInfo class has been added into scripts/build/config.py.

Components: AOSP, Framework

Change-Id: I4b5b78c0d4d3aff248887ba5ced0c91081e24e6b