This commit is a bit early, but it'll save Stef, Henri and me much
 time later, when we don't have to backport modifications to input_*.c

   What's new :
    - playlist works again (still the old wrong way like Meuuh doesn't
    like, but this is going to change within a few hours)
    - input_ps, input_ts and input_dvd are now plugins, located in
    plugins/mpeg/ and plugins/dvd/

   What's broken :
    - audio output might be broken on some streams ; have to investigate

   What has changed :
    - fast/slow keys are now A/Z instead of A/S since S was already
    linked to the scale/noscale toggle.
    - `--dvd' doesn't work anymore, for the moment try to use :
     vlc --input dvd /dev/dvd
    - module bank is now less verbose ; use `--warn 1' to turn back
    verbosity on