This allows a more reactive pause (independant of *-caching value). It is
not yet instantaneous as vout/aout still play their buffer.

It is mostly clock fields renaming.

It fixes clock prototypes.

No functionnal change yet.

The input main loop will now handles space control at the right place.

 It was a big race condition, please understand how multi-thread works before
touching core files.
 Do not throw away the few first subtitles.

This fixes a few "deadlocks" with input waiting for playlist, while
playlist is waiting for input event.

This removes the need for suxor_thread_t.

The record access_filter will become useless as soon as all demuxers that can
support it will be modified.
The record support is half done. I will also add es_out_t record functionnalities,
and a way to selected one of them if both are supported.

Otherwise, every one would have to check the return value of var_Get ...

Patch by Rov Juvano. thanks.

Currently libvlc uses "state" callback to notice input state changes, and the playlist notice input state change via direct call from the input.
playlist can't use the "state" variable as it is also used by the playlist to ask the input to do a certain action.

The event approach is much more clear here.

Simple demo:
vlc --sout="#duplicate{dst=display,dst='transcode{vcodec=mp4v}:std{access=http,dst=0.0.0.0:8080,mux=ts}'}" --ignore-config  --use-stream-immediate movie.avi &
vlc --use-stream-immediate http://127.0.0.1:8080
and
vlc --use-stream-immediate http://127.0.0.1:8080 --auto-adjust-pts-delay

You'll have to wait a bit until the pts delay is auto adjusted. Generally it takes 2-4 seconds, because access set a very high default pts delay value. One amelioration would be to lower the pts_delay when this option is set to allow a quicker convergence.

The general algorithm requires some tuning, but results are here.

Note, this only works if there is a video track. A similar function could be developped for the audio tracks.

It needs to be done by the parent (VLM or playlist)

Remove VLC_META_ENGINE_*
Don't use VLC_META_INFO_CAT
Avoid using input_Item{Add,Get}Info
Remove disabled code in cdda
Remove "meta fetcher":
    There was only 1 module (not) implementing it (musicbrainz)
    Reduces complexity in playlist core
Use a more consistent naming
Factorize QT4 sorting and column display code
Remove unused members

This improves readability a lot and prevent us from reinventing the wheel.