Draft for libGDX Pay API.
Purchase object improved to accept both an integer or String in the constructor for the item identifier.
Merge branch 'master' of https://github.com/noblemaster/libgdx into iap
added gdx-pay to build
Merge branch 'master' of https://github.com/libgdx/libgdx
Merge branch 'iap' of https://github.com/libgdx/libgdx
Pay API:
 - removed PurchaseObserver - there is now only 1 single listener: PurchaseListener
 - itentifier changed to String (from int).
Merge branch 'iap' of https://github.com/libgdx/libgdx
Added payment processor stubs for Google Wallet/GWT and Stripe/Desktop.
Added a 3D benchmark test and benchmarking utilities.
The test also intercepts Gdx.gl now.
Measure useProgram instead of attachShader
Created an equals method for the rectangle object.
Adding proper hash code method to Rectangle so that the equals method functions appropriately.
Improving equals to by using Float.floatToIntBits
Renamed GLBenchmark to GLProfiler.
Cleaning up JavaDoc comments.

As to follow the file's javadoc style (see toString above), I remove the @Override marker.
Made SelectBox account for list background size

Addresses issue #1982
Removed ProfilingModelBatch. Added static helpers to GLProfiler. Added primitive counter to GLProfiler.
Fix TextureUnpacker