Modify processBuffer to take the number of audio sample to produce.
buffer_out which is a shared buffer used by AudioMixer is now INTERNAL_BUFFER_SIZE
INTERNAL_BUFFER_SIZE is 128K by default
Moved all initialization stuff in SDL_GUI.cpp.
There should be a "place" for this...
there is no need of SDL_gfx
Merge branch 'master' of github.com:yoyz/audio
Include the directx8 sdk because for now it is needed for building the apps on windows.