Minor headers cleanup

  - It should also no longer crash if you select macosx as an extraintf. This is not allowed. It is the cause of the NSDictionary crash reported often in the forums. Notice however that if you have selected a primary interface that is not macosx, you might end up with a "blank application" forcing you to reset the preferences manually (your fault for mocking with them in the first place).
  - Should fix clivlc mode. (this mode allows you to run VLC on OSX while no user is logged in, in the GUI).

Thanks to Jean-Michel Vallat for kicking my ass. :D

* Free scandir results when we are done with them. Issue pointed out by jmvallat_vlc at mac dot com.

* Enable liveMedia's RTSP over HTTP mode. This is something first used by QuickTime, and useful to get around annoying and dense NAT/firewall/proxy setups.
  --rtsp-http enables the HTTP tunneling. --rtsp-http-port allows you to choose which port. The default port is 80.

header from internal headers. 
Patch elaborated with Olivier Aubert.

Makefile.am: target 'package-win32-base-exe' is now a bit smarter when looking for makensis, which also cover cygwin. Hence, target 'package-win32-base-exe-cygwin' is now redundant

  Tested against the WAV 6ch Speaker Test from SeeMoreDigital.net (Validated against QuickTime Player)

* Don't upmix the channels if we only have Stereo or Mono audio. Let the device setup take care of that.

* ran 'make update-po' to get everything in sync again (the previous commit was targetted for 0.8.4a, but the translation was a bit too slow)