In MSVideoQualityController, change the control mechanism of the FEC. The FEC parameters are adapted to the available bandwidth, given the loss rate and the current bandwidth dedicated to the FEC, that is given by the overhead.
The search of the best video configuration encoder is done after to take the bandwidth needed for FEC into account. The FEC parameters are finally updated. This update is made for each TMMBR received and when the timer delay is over.
Add a new timer of 20s for FEC to check the current FEC parameters at regular intervals and adapt them.
Add a loss rate estimator computed on a large window (15s), to be robust to noise. It is send as input for the update of the FEC parameters.

Update tools/mediastream.c for FEC.
FIXME: the case where the FEC is disabled does not work like without FEC when tools/mediastream.c runs.

Update the fec session creation in Mediastream.
Add the bandwidth used for the FEC in RTP statist...