* we might want to store the streams in a session and have a session_start()
  that calls start() on all the streams
* add a stream ready signal
* add local in names where appropriate
* move directyion out to the stream
* inherit codec list from session initially
* add doc that codec lists are priortity ordered
* add accessor for the set of common codecs
* change optional_params to a datalist
* document farsight_codec stuff
* make rtp plugin choose an unavailable port, its hardcoded at the moment
* consider having to recv as soo as you info is sent (before sending)
* consider the fact that calls will have priority and must ensure that it can
  happen in any situation

long term
---------
* gobjectize FarsightCode, FarsightTransportInfo, etc.
* add gtype for list of  FarsightCode, FarsightTransportInfo, etc.
