+ [BUG] A work around for 8 bit samples being stereo reversed with SDL_mixer.
+ Also check the return value of Mix_SetPanning, and raise an
+ error on volume errors.
+ [BUG] Changed default chunk size for pygame.mixer to 1024*3. Which is
+ the magic number which stops scratchy sounds on most systems.
+ However it does make sounds a bit laggier... it's best provided as
+ a config item for users.
Updated pygame.display.update() to release the GIL whilst doing things,
so other threads can do things whilst it's updating the screen.