Add Icecast protocol

Icecast is basically a convenience wrapper around the HTTP protocol.

Signed-off-by: Martin Storsjö <martin@martin.st>
fate: explicitly set the default THREADS value

This makes the default of '1' more explicit than defaulting to '1' in
fate-run.sh and regression-funcs.sh if THREADS is not set.
Fixes the reported thread count in fate-cpu if THREADS is not set.
Merge commit 'eb9244f20210fd420fb9b3c98126f9cae525d1cc'

* commit 'eb9244f20210fd420fb9b3c98126f9cae525d1cc':
  Add Icecast protocol

Conflicts:
	Changelog
	configure
	doc/protocols.texi
	libavformat/icecast.c
	libavformat/version.h

See: e3dc2c86fc4178b100484c54f12c88705cdf6724
Merged-by: Michael Niedermayer <michaelni@gmx.at>
Merge commit '23dfa00b88fc927d4c1854ab4fc60f5c6398f3ac'

* commit '23dfa00b88fc927d4c1854ab4fc60f5c6398f3ac':
  fate: explicitly set the default THREADS value

Conflicts:
	tests/Makefile

Merged-by: Michael Niedermayer <michaelni@gmx.at>
x86/hevc_mc: remove an unnecessary pxor

Signed-off-by: James Almer <jamrial@gmail.com>
Reviewed-by: Mickaël Raulet <mraulet@gmail.com>
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>