[Vorbis] Reg: specimans for oga and ogx

[xiphmont at xiph.org]

.oga is any non-vorbis audio stram encapsulated in Ogg (eg, Speex, or CELT).

.ogx is just a catch-all for something that doesn't strictly fit in
.ogg, .oga or .ogv.  The extensions actually don't really mean
anything except as a helper suggestion to tie a media type to a
specific player application.  The underlying files don't actually
differ in structure (except for the old .ogg, which implies Vorbis
only).

Monty