- Make MPEG audio (and other audio types besides AC3) work.

- Make MPEG audio (and other audio types besides AC3) work.
- Since the stream is closed after the scan then reopened by reader, we have to preserve all the state we gathered during the scan (like audio id to TS PID bindings) across the close. For now do this by ignoring the close call & doing a close internally when a stream of a different name is opened.
- Don't overfill ts_packetbuf and abort just because an audio stream was missing the AC3 sync pattern (MPEG & DTS streams don't even have an AC3 sync pattern).
- Get rid of several unused variables so that this compiles with no warnings.

git-svn-id: svn://localhost/HandBrake/trunk@1231 b64f7644-9d1e-0410-96f1-a4d463321fa5