Fixes #501.
OEGameCore: added setCheat method for passing cheat code, type and (bool)enabled from UI to core
Fix leaking bound IOSurface texture when rendering a core that supports OpenGL.
Allow cores to set the audio bit depth

32-bit = considered float
Set mBitsPerChannel properly
Also missed setting mFormatFlags properly (only affects theoretical float support)
Zero fill audio if needed
Merge remote-tracking branch 'upstream/master'