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.