* Add code to pace sending a stream when it is being sent from a file.

  We limit the datarate to twice the average datarate (however the first
  few seconds are sent flat out to help with prebuffering).
* Add the initialization of the rc_eq fields and the like for VIDEO codecs.
* Add the missing get_arg calls for VideoQxxxx

Originally committed as revision 920 to svn://svn.ffmpeg.org/ffmpeg/trunk