From Rafa Gaitan, "I finally had some time to change the build system for Android using a Toolchain, which, I think, will be easier to maintain and uses cmake standard system to build it.

My changes:
-------------------
- I changed the cmake files and added a toolchain for building OSG in Android. The toolchain is based on the one used at OpenCV. For building OSG for android you just need to do:

    mkdir build_android_static_gles2 && cd build_android_static_gles2
    cmake .. -DANDROID_NDK=<path-to-the-android-ndk>
                  -DCMAKE_TOOLCHAIN_FILE=../PlatformSpecifics/Android/android.toolchain.cmake
                  -DOPENGL_PROFILE="GLES2"
                  -DDYNAMIC_OPENTHREADS=OFF
                  -DDYNAMIC_OPENSCENEGRAPH=OFF
                  -DANDROID_NATIVE_API_LEVEL=15 # optional
                  -DANDROID_ABI=armeabim #optional
                  -DCMAKE_INSTALL_PREFIX=<path-to-the-install-path> #optional
make -j 8
make install

    The OPENGL_PROFILE works as expected, changing it to "GLES1" it builds and links OSG using GLES1.
    The DYNAMIC_OPENTHREADS/DYNAMIC_OPENSCENEGRAPH parameters also allows to build the dynamic libraries

- I also added some build fixes for android related to the texture formats and added some missing USE_OSG_SERIALIZER_WRAPPER in the osg serializer library to support loading osgb files in static."


git-svn-id: http://svn.openscenegraph.org/osg/OpenSceneGraph/trunk@14514 16af8721-9629-0410-8352-f15c8da7e697