Merge pull request #784 from CartBlanche/develop3d

Develop3d : Changes to allow PlayStation Mobile to compile again, after recent changes.
Merge pull request #781 from dellis1972/develop3d

Fix for #723 (SpriteBatch 2D only drawing)
Merge pull request #777 from slygamer/accelerometer

Microsoft.Devices.Sensors implementation for Android (TEST)
Android rendering issues resolved
Added GraphicsExtensions.CheckGLError().  Has a Conditional("DEBUG") attribute so it only exists in builds with a DEBUG conditional.
Added call to GraphicsExtensions.CheckGLError() after every GL call.  Found several problem areas on Android.  Performance in Debug builds does not appear to be affected much, if at all.
Attribute vertex locations are no longer hard-coded.  Locations are retrieved after linking the shader program.
Added call to GL.UseProgram() before calls to GL.Uniform1() to prevent InvalidOperation error.
Retrieve maximum number of texture image units from OpenGL and use that number to initialize TextureCollection and SamplerStates in GraphicsDevice. Prevents error from using out-of-range index in GL.ActiveTexture().
Merge branch 'develop3d' of https://github.com/mono/MonoGame into android-texture
Return SoundState.Stopped for non looping sounds and add some missing #if's
Merge branch 'android-render-fix' of http://github.com/slygamer/MonoGame into slygamer_android-render-fix
WINRT now sets the viewport when the client window changes size to match XNA behavior.
Fixed a compile error in the Linux project
Avoid exceptions when resuming and GL context was lost on Android
Merge remote-tracking branch 'upstream/develop3d' into develop3d
Removed the copyCount variable from vertex buffer copying code.
Fixed issue #672: Gamepad analogue sticks & Accelerator don't work

Initialize GamePadState with values (was initialized without the actual data from the gamepad).
Make iOS compile again
Updated accelerometer and compass to match the android version
Fixes #797. Too lazy to add an another pull request.
Made landscape games work again on iOS 6
TODO: GameCenter requires portrait to work without crashing. Find a way to prevent the game from rotation to anything other than landscape.
Whoops, that's for iOS 6
Clear SamplerStateCollection and TextureCollection when device is initialised.
Clear GraphicsDevice._enabledVertexAttributes so they get re-enabled.
Merge branch 'develop3d' of http://github.com/mono/MonoGame into develop3d