demux: add "BIKb" FourCC

More support for the worst codec ever.

Signed-off-by: wm4 <wm4@nowhere>
vd_lavc: by default, do not show corrupt frames

This flips the default value. Use --vd-lavc-show-all=yes to revert.
manpage: --ad-spdif-dtshd=yes works now

It was fixed a while ago. There are still some issues, as pointed
out in the manpage addition.