FMJ revision 81: Mitigates deadlocks related to synchronization source identifier (SSRC)-related information lookup.

Adds some missing licenses in copyright file and skips some packages when creating debian src package.

FMJ r73: Fixes a deadlock between JitterBuffer and RTPSourceStream. ICE4J r467: Does not use instanceof on each and every RTP packet.

Fixes removing ssrcs, a bug where this leads to grow in csrc list in MediaStreamImpl when in one call we have changing of ssrc (the call is one2one).

Reduces the number of times that a received packet is internally copied. Reduces the scopes of synchronization blocks and breaks synchronization blocks into multiples on different objects. Optimizes hashtable iterations. Fixes warnings. (ice4j revision 463)

Updates debian src package. Comments on mentors: not needed file control.binary.pkg and description for usrsctp and libmkv.

Attempts to improve the detection of speaker switches performed by the dominant speaker identification via a uniform notion of "silence" among the conference participants.

Supports debugging the 'Dominant Speaker Identification for Multipoint Videoconferencing' implementation through the REST API of Videobridge.

Adds AdvancedAttributesAwareCodec that can handle attributes that are valid for all codecs and fixes parsing them. Adds handling of ptime for one of the codecs.

Use the remote bandwidth estimator for REMBs reported by the MaxThroughputBridgeRTCPTerminationStrategy.