postprocessing cleanup:

postprocessing cleanup:
remove opendivx #ifdefs
remove rk1 filter
remove unused / obsolete stuff
add -1,4,2,4,-1 deinterlacing filter (ffmpeg uses that)
threadsafe / no more non-const globals
some optimizations
different strides for Y,U,V possible
remove ebx usage (someone really should fix gcc, this is really lame)
change the dering filter slightly (tell me if its worse for any files)

Originally committed as revision 7947 to svn://svn.mplayerhq.hu/mplayer/trunk/postproc