This should fix spurious BadWindow errors from the video displays.

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

Items are stored twice, once in a tree structure and once in a one-level list.
This patch removes attempt of the playlist_TreeMove() function to move both tree and
one-level instances of an item.

Firstly the reason is that function was not effective in this attempt.
And secondly, the attempt itself doesn't make sense in some cases: you can always
map moves within the tree to moves within one-level, but you can't always do it
the other way around, it is in most cases ambiguous.

Moreover, this patch restricts moves in the tree to within the present parent of the
item being moved. Again, in most cases, moving an item out of its parent or into another
parent is meaningless.
Signed-off-by: Rémi Denis-Courmont <remi@remlab.net>

Fix segfault when dropping more then one item onto an item in the left side selector.

Also copy instead of move items when dragging from media library to playlist and the opposite.
Signed-off-by: Rémi Denis-Courmont <remi@remlab.net>

The Timer Queue Windows API is not available on WinCE, so this is a
rewrite based on timeSetEvent() and friends. It's not safe yet with
regard to timer deletion.

No need to store/recreate metadata on plitem anymore, as we can get
it now on the fly, also separate headerData and Data. Hopefully
that vlc_gc_incref/vlc_gc_decref is sufficient for that input_item_t
pointer protection.

Feel free to fix/revert/comment if that pointer shouldn't really be
there, or if it's not safe it to be there thisway.

WinCE needs the cancellation event handle along with the thread handle,
so we have to switch back to a struct on WinCE. Which causes great
ugliness. Fix the build with the recent changes, and simplify some
related Win32 code.

Fix memleak + event leak on wince if thread creation fails

Skins2 dll gets a bit smaller.

At least, ES track switching became really slow (the data for the associated
ES are not buffered as the decoder is not present).

There is still a problem when the Gui itself has "on top" set.

Pointed-out-by: Jean-Baptiste Kempf

This fixes always-on-top going away when toggling full-screen and back.

We were accessing some main interface variables from random threads
without serialization. This simply moves the blocking connection signal
from sole size setting to the whole video widget request call. In the
process, we can remove two signals. We still need a blocking connection
signal. It does not add any new deadlock case, since there was already
blocking connection signal in the same call and in the same direction.

(Otherwise we would be in trouble whenever VLC crashes)

Remove repeated code