Add the multiplex doc to the distribution.
Add the multiplex doc to the distribution.

svn path=/trunk/ogg/; revision=9460

youfearm3/ogg,ShiftMediaProject/ogg,nicolaichuk/ogg,emscripten-ports/Ogg,felipebetancur/ogg,brion/ogg,ShiftMediaProject/ogg,ksophocleous/ogg,eidy/libogg,nicolaichuk/ogg,xiph/ogg,youfearm3/ogg,xiph/ogg,mwgoldsmith/ogg,mwgoldsmith/ogg,brion/ogg,emscripten-ports/Ogg,felipebetancur/ogg,ksophocleous/ogg,eidy/libogg