mpeg4 b-frame enoding support
removed old, out-commented ratecontrol
reuse motion compensation code between encoding & decoding
prefix newly added global functions with ff_ to reduce namespace polution
b-frame ME (unfinished, but working)
added some comments to mpegvideo.h
do MC on encoding only once if possible
bugs? ;)


git-svn-id: file:///var/local/repositories/ffmpeg/trunk@403 9553f0bf-9b14-0410-a0b8-cfaf0461ba5b