Add CODEC_ID_GSM and CODEC_ID_GSM_MS to ffmpeg audio codec list. (mostly useless but it doesn't hurt. needs ffmpeg to be linked with an specific lib)

 We use vlc_UrlParse for "URL" without protocol... so it was using a part of
the URL as a protocol if it found ":/". Ensure to extract only valid protocol
at least.

- Use net_Accept()

- Fix som bugs

- Poll the system clock only once per loop (yes, it DOES matter),
- Fix rare bug with TLS and multiple listening sockets,
- Do not try to read/write to client socket with no pending events.
...and of course introduce dozens of new bugs.

This SHOULD speed httpd up a bit.

- Accept phony SDPs with multiple identical media lines as if they had a single one

	fixed mpeg audio decoding)
vlc_demux.h: fixed COMMON_INIT_PACKETIZER (create a packetizer and not a decoder,
	fixed mpeg audio packetizer)

Treat all live555 versions before LIVEMEDIA_LIBRARY_VERSION_INT 1171929600 as if playStartTime() and playEndTime() didn't exist. Now only handle unpatched current versions of live library.