Pass drap&drop coordinates over to visual controls.
This feature will be used to allow users to finely insert items in the
playtree control instead of just appending them at the end.

Hand-crafted code in plugin descriptor is not allowed. And the code was
unsurprisingly buggy.
This reverts commit 1c2a95b8.

Conflicts:

	modules/codec/schroedinger.c

macosx: fixed volume normalizer prefs and crash when saving the Growl option in combination with some config sets

It is a preliminary work.

It is looking more natural.

It allows to use hw decoding (whereas it was always disabled).
It workaround a bug in ffmpeg/libav.

It avoid tearing depending on the default settings.

 * Add a dispatcher method for tracklist properties
 * Implement Tracks and CanEditTracks

restricted to the audio and video filters.

This happen when p_vids->p_bih->biSize - sizeof( BITMAPINFOHEADER ) = 0
and the data is in p_vids->i_chunk_size, because then p_extra == NULL.

This solves the fruity sample crash but doesn't fix the palette