Some functions renamed

Fix 1102

Align formating with other raylib modules coding style.

There could be some cases where we need to define the internal audio buffer size, now it's possible.

RENAMED: InitAudioBuffer() to LoadAudioBuffer()
RENAMED: CloseAudioBuffer() to UnloadAudioBuffer()

Renamed some defines and reviewed some comments.

Check if provided path is a full path containing system root letter: C:\

It seems there is some problem on drawing... :(

Not exposing some data structures