Introduces a flag that disables SRTP extensions in DtlsControl so that it can be reused in non RTP streams.

Adds method for sending data over DTLS layer to the transformer. Returns application data packets from transform method.

Fixes unknown error in usrsctp_connect on Windows. Propagates IOExceptions as an error back to usrsctp stack. Adds transfer test.

SCTP stack will be never deinitialized for the time beign because of the deadlock in usrsctp_finish(). Minor fixes.

Implements DefaultTlsServer.getRSAEncryptionCredentials() which may be required by certain cipher suites.

Fixes the list of cipher suites supported by the DTLS server so that it reflects the capabilities of the actual Bouncy Castle implementations at this time.

Protects against JVM crash when closed SCTP socket is used by checking for null pointer and throwing IOException. Adds unit tests for SCTP wrapper.

Cleans up the background Threads associated with TURN candidates more explicitly/aggressively/thoroughly in an attempt to mitigate a leak of such reported by Enrico Marocco.

Lets RTP packets generated from mute data sources from time to time in order to fix an issue at the receiver which could cause it to get out of sync with respect to the SRTP index of the sender. Issue reported and fix suggested by Emil Ivov.