Missing routines:

- RGB->RGB (MMX): 24->*, *->24, RGBA ->*

- YUV->RGB (MMX): * -> RGB24, * -> BGR24

- RGB->YUV (MMX): Complete missing

Other stuff:

- Enable passing of YUV Coefficients

- Seek accelerated memcpy replacements and test them (avifile, mplayer)

Port audio stuff to gavl:

- Port interleaving routines.

- Port sample conversion

- Port mix routines

