* modules/codec/theora.c, configure.ac.in, modules/codec/Modules.am: new

* modules/codec/theora.c, configure.ac.in, modules/codec/Modules.am: new
   theora codec plugin.
   This plugin is based on the experimental theora codec from the Xiph.Org
   foundation (http://www.theora.org/). Because the theora bitstream
   specifications are likely to change in the near future, this plugin won't
   be compiled by default. If you want to test/develop theora with vlc, you'll
   need to configure it with --enable-theora and also make sure you've got a
   fresh libogg from cvs.

* modules/demux/ogg.c: modified to handle theora and tarkin bitstreams.

* modules/codec/tarkin.c: fixed a few typos.