New AVFoundation video capture module for Mac OS X

This module lets you capture video devices with the AVFoundation framework on Mac OS X.
It is an upgrade of the qtcapture module. Currently no GUI integration yet.
Only available via command line

Usage: avcapture://

Signed-off-by: Felix Paul Kühne <fkuehne@videolan.org>
Update NEWS and LIST for AVFoundation video capture module
configure.ac: fix linking the OSX UI module if the AVFoundation framework isn't present (read: OSX 10.6)
THANKS: merge updated and more complete contrib copyright list
Simple: slightly different matrixes for 7.x and 6.1 stereo downmix
simple: use single precision maths (rather than double)
THANKS: add missing GPL-licensed contribs
mmdevice: drop to zero priority for now
goom: force FL32 input
projectM: force FL32 input
visual: force FL32 input and set output format
vsxu: force FL32 input
configure.ac disable/don't load avcapture module and its framework if AVFoundation is not present (OS 10.6)

Signed-off-by: Felix Paul Kühne <fkuehne@videolan.org>
configure.ac: replace == with =

Signed-off-by: Rafaël Carré <funman@videolan.org>
os2: add vlc_getProxyUrl()

Signed-off-by: Rafaël Carré <funman@videolan.org>
visual: remove non-sensical code

This mostly reverts commit fc5156cc00225de64eb9b8715809c6a84e48b35e.
This also fixes a use-after-free bug.
visual: privatize filter_sys_t, etc.
visual: do not keep unused fields
visual: remove write only field psz_args
visual: reduce symbols count