Two fixes were involved, firstly, access unit delimeters were used to denote access units and the Write timeout on rtmpSender's ringBuffer was
increased to stop the 'unable to dump old write' errors. Also made some small changes elsewhere that should fix future issues, particular with
MTS output.
Renamed the RTPLexer to Extracter, renamed NewRTPLexer to NewExtracter and renamed Lex to Extract. Put Extracter and accompanying methods in file extract.go.
Put tests relating to Extracter in extract_test.go.