Add info about MHM's CIF TREE.

Untested so far, of course :) . But using file entries from the STD CIF
TREE makes it seem incredibly plausible.
Add CIFTREE support for game 3 and theora encoding for avfdec.

Important to note is that the theora encoding function doesn't free the
encoding context, because the designated function to do so causes a
double-linked list corruption (???) .

These two disparate features are in one commit because I accidentally
forgot to commit the CIFTREE support before working on the theora bit,
and some files were modified by both features, making it too much of a
bother to separate the features into commits. Sorry 'bout that :P .
Get rid of this ugly, ugly make-an-ogv script.

This is because I didn't realize at the time that interfacing with the
theora library is something I could do, got a bit too used to the
commandline I think. In any case, you don't need this anymore, avfdec
can do it for you.