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

It's causing too much trouble in testing.

No more short-term plans, and it really should get out soon.

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.

Certain breakage in the example configurations can now be detected
automatically.

This is an attempt to resolve a coverity false positive in a somewhat
sane way.