if not managed, vlc terminates with a "vlc: Fatal IO error: client killed"

It closes #3339 (the stream is correctly detected), but as the 302M content is
not PCM data (probably AC3 or Dolby E), the audio is not correctly decoded.

Close #3347

Close #3348

 It is ugly to have this list of codec id (as it can become unsynchronized), but
ffmpeg does not provide a way to retreive this information :(

picture_New() will now always return a picture having
 - pitches multiple of 16.
 - chroma pitches multiple of the luma one.
 - a bit of extra height (as it can helps some ASM functions).

This reverts commit 46626b9d.

Dead code.

They caused much confusion from bug reporters and support requestors.
Feel free to add more explicit and specific errors after module_need()
call sites in failure cases.

And no the test is not broken. libvlc_media_get_tracks_info() is.

This reverts commit 9a2adcfd.

Oddly enough, this was correct in VLC 1.0.