Put compiled binaries to bin subfolder
Add fixes.txt for memo
GCW0: Force 60Hz, should be more compatible with gcw-zero
SDL: GCW0: Synchronize drv.cpp for sdl and gcw0; no real use, just the path of future unifying
GCW0: Enable libao compilation by default both for gcw0 and mingw build
GCW0: Move sound code to separate files.

  snd.cpp - now contains general data and audio driver choosing
    sdlaudio.cpp - SDL audio backend
    aoaudio - libao audio backend