Blender Git Loki

When ffmpeg format is selected, make 'Video' and 'Audio' panels
as tabs of the format panel (was annoying how the format panel
would jump far to the right after selecting format' Thanks ao2
for noticing.

Note: as self-appointed code weenie, I should point out that the
ffmpeg code has a lot of tab/space indenting mixed in nasty
ways -- this should be fixed.