... but keep it in cmdline.c (for now) to "follow the pattern".

Adds support for WebM/Matroska
Replaces Vorbis and Theora with Ogg

The correct way is to just not configure an encoder for a stream, which
is what the documentation already states. Encoder sections now require
a program name to be set or the configuration will not load.

Fixes a segfault in ezstream.c, as reported by Tom McCallum via Github.