1. The applet sends a keyframe only once on the beginning of sharing
2. The server sends keyframe when a "late" participant joins by having the client request to send a keyframe
3. Most of server code re-written in scala
TODO: cleanup and logging
git-svn-id: http://bigbluebutton.googlecode.com/svn/trunk@3776 af16638f-c34d-0410-8cfa-b39d5352b314