[ogg-dev] liboggplay and overlay video

[ogg.k.ogg.k at googlemail.com]

> I think adding an RGB/RGBA frame type to liboggplay should *also*
> happen. yuv2rgb is tedious at best and hard to get right at worst, so

I'd added an RGBA type, but if this is going to also carry video,
it might be better to merge this with the existing video type, and
have a 'type' enum, or just several pointers, only one set being
non NULL (makes client code simpler). Would it be annoying to
users if the exposed struct was being changed (since I hear that
liboggplay is being used by Firefox) ? At the moment, changes
are limited to additions to the API.

Thanks