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.

As for qt4, offering the possibility to deactivate automatic resizing
is desirable. Reusing the qt parameter is not a problem for skins since
qt4 is a prerequisite.

TODO, rename this parameter with a more interface agnostic name since
the need is for all interfaces.

For a video control, default values are contradictory, in
a sense that a video control is not resizable and autoresize
is true. By default, this results in skins resizing to fit a new video, but
the inner video not using this extra space. (see AirFlow for instance)

This patch ensures that if autoresize is true, default behavior for a video
 control is to be resizeable.