fen: any suggestions for the other Control() stuff?

   - searching is a mess
   - autodetect not yet activated, force by opening the idx as subfile

* src/video_output/vout_subpictures.c: modify the scaling factor based on the original video size info.

    + Fixed previously broken DVD support.
    + Removed currently broken Speex support.
  * debian/control:
    + Build-depend on libdvdnav.

  TODO: create the index
        position control

* modules/video_filter/time.c: stick to our config options naming convention + fixed a couple of mem-leaks.

   + major cleanup and bug fixing.
   + added support for spawning and controlling several media instances.

* src/video_output/vout_subpictures.c: support for stacking subpictures filters (eg. --sub-filter=foo,bar).

* vobsub.c: rewrite of the vobsub module. Now has track support. This is UNFINISHED.
  TODO, repair the 'Control' commands store the timestamp/location combo's in the arrays of subtitle_t structs

  and find a way to pass the info from the decoder to the core of course....

fen-trick
time.c: fixed a few copy/paste bugs and some warnings

  + improved spu_SortSubpictures() to deal with SPU channels.
  + ephemer subpictures can also have a stop date now (allows more flexibility).