MSRtpSend can make use of it so that sending of RTP packet is perfectly aligned with the tick time (but with a fixed delay of at most one tick duration)

This prevents ignoring delayed responses if a new transaction has been
added by a pair.

If the first ICE candidates to be found are relay candidates wait a little for better candidates before nominating them.

Split init and exit in the two mediastreamer libraries to prevent undefined reference errors at compilation on some systems.