stream: remove VCD support

If a single person complains, I will readd it. But I don't expect that
this will happen.

The main reason for removing this is that it's some of the most unclean
code remaining, it's unmaintained, and I've never ever heard of someone
using it.
m_option: use isfinite() instead of isnormal()

This accidentally rejected d==0. We can actually deal with sub-normals
fine, we just want to exclude nan and infinity (although infinity is
already accounted for, but anyway).
vo: correctly initialize parameters in corner cases
command: improve video-bitrate property

Signed-off-by: wm4 <wm4@nowhere>

Includes some cosmetic changes over the original PR.
demux_lavf: support new rotation metadata API