* ALL: got rid of *_Probe functions because most of them were duplicates

  * ALL: got rid of *_Probe functions because most of them were duplicates
    of the real _Init or _Create functions. That's 1000 lines of code gained.
  * ./src/misc/modules.c: we try not to keep the global lock in module_Need,
    which should speed up output spawning.
  * ./plugins/dummy/input_dummy.c: fixed vlc:quit command.
  * ./plugins/gtk/gtk_playlist.c: compilation fix.
  * ./plugins/macosx/*: preliminary fixes for the vout4 port.

   Notes on the *_Probe eradication:
  o I probably broke the DirectX video output, because of the "must init and
    run in the same thread" issue. I'll fix this ASAP.
  o Subtitles are broken (or at least, pretty ugly) in RGB mode.
  o The input plugins still have *_Probe functions. This will disappear when
    meuuh is finished with the access plugins.
  o The decoder plugins still have *_Probe functions. This is probably not
    going to change, it looks OK to me.