legacy macosx intf: make sure we display the right playback button graphic when drawing the video window

 * plugin cache identifier string,
 * HTTP user agent header,
 * configuration file head comment,
 * CGI server software name.

In several cases, it is not used because of atexit().

This reverts commit 8b40fb0f.
Reading the PulseAudio source code, #2538 seems wrong.

Conflicts:

	bindings/python

Nothing uses it and it is irrelevant after tree form and list form
playlist representations were joined.

- New function to copy a playlist item and all its children.
- Allow node creation at any position in parent.

Fixes #3406

This triggers a race condition and ultimately a crash when the input
kills all its children.

Ref #3406

This fixes #3377.

Signed-off-by: Jean-Baptiste Kempf <jb@videolan.org>

Signed-off-by: Rémi Denis-Courmont <remi@remlab.net>

Removes a lot of hacks, especially around manipulating size (no more sizeHint(), very limited use of doComponentsUpdate and updateGeometry() ),
Simplify the number of starting options of the interface
Fixes crashes due to QStackWidget limitations
Still a lot of debug around, but mostly commented out, that will go in future commits
Close #3401
Close #3210
Close #3332
Close #1717
Signed-off-by: Jean-Baptiste Kempf <jb@videolan.org>

For skins without video elements, fullscreen mode could be launched with the inner video kept hidden. Initializing the video control to NULL fixes it.