skins2 expects notification to occur if and only if the variable really changes.

This patch fixes things for And and Or variables.
This fixes trac #4529

This trick only works if the action ends up in the state really being toggled.
This is not always the case and can then lead to undesirable effects,
for instance the play button going to pause when no playback is underway.

This trick was needed to prevent visual artefacts when refreshing was a heavy
task, but is no longer needed since refreshing has been heavily optimised.

This reverts commit 7d3c30f9.

As specified in the MSDN documentation
It will warn, though

This is way cleaner and should help supporting deinterlacing without
memcpying full images (hopefully)
Signed-off-by: Jean-Baptiste Kempf <jb@videolan.org>

This patch makes volume more consistent with the rest of vlc :
 - volume is now advertised on a 0-400% range instead of a misleading
   0-100% range. This fixes the discrepancy between volume displayed
   within the skins and volume displayed via OSD
 - "qt-volume-complete" and "volume-step" are now taken into account,
   which makes skins2 more consistent with qt4

Also, remove leftover _intel parts here and there.

This is equivalent and better supported on Mingw
And, remove an outdated comment

From the wine project, modified by Jean-Baptiste Kempf

Remove GUID that are already in wine's headers

This fixes quite a few .idx samples that didn't work before.

Not in the mingw .h but seems to be in the .a

Contains no translatable string

This replace with a set of headers from the Wine project, modified by
Jean-Baptiste Kempf