* modules/gui/macosx/vout.m: removed some code that was preventing us from
  using chroma converters.
* modules/codec/quicktime.c:
  - added the video decoder. only works with SVQ3 atm, returns Invalid
    BITMAPHEADER for some reason in all other cases.
  - did some cleaning up. this might just work under Win32 now aswell,
    gibalou will do some testing tomorrow ;)
  - SVQ3 QT degrades faster then the ffmpeg version, but also recovers
    faster. I'm not yet sure which one i prefer.