Fixes for the libtheora decode API wrapper.

Fixes for the libtheora decode API wrapper.
Formatting now matches the rest of the code.
Functional fixes:
- The lifetime of the theora_info and thera_state structs are now completely
   independent.
  You can clear your info struct as soon as you initialize a decoder, or
   initialize multiple decoders from a single info struct.
- The decoder is initialized from the values in the actual theora_info struct
   passed to the API, not the internal th_info struct filled in by
   th_decode_headerin().
  This should support whatever kinds of cleverness someone who is not using the
   Ogg encapsulation might come up with to avoid constructing header packets.

Currently only tested with libtheora's player_example.

git-svn-id: http://svn.xiph.org/trunk@11682 0101bb08-14d6-0310-b084-bc0e0c8e3800