Merge pull request #80 from attilaz/master

added apple device's drawstress results
Added support for blend separate and blend MRT independent.
Merge branch 'master' of github.com:bkaradzic/bgfx
Added missing files.
Added 19-oit example.
Added blend independent caps debug info.
Ignore blend independent when not supported.
Added GL_CHECK_I macro to ignore GL errors.
Fixed compile error.
Fixed draw buffers.
Removed debug code.
Cleanup.
Increased GLSL compiler MaxDrawBuffers to 8.
Cleanup.
Updated README.
Fixed debug marker extension check.
Renamed glext to khronos.
Updated glsl-optimizer.
GLES3 fixes.
Simplified API, removed difference between vertex and fragment shaders.