Blender Git Loki

Bring back support of FFmpeg >= 0.7

After planar codecs support minimal FFmpeg was
bumped to 0.10 which was not so much nice because
it was only released only later last year.

Didn't find a way to make compatibility code local
in ffmpeg_compat, so there're some ifdefs in
audaspace and writeffmpeg.

Not entirely happy, but having a bit of ifdefs in
code better than lots of real PITA for platform
maintainers.