Qt4 - Input Manager: cleanup, fix behaviour of enableVideo(), initialize variable that can be used and renaming.

- nice images
- fix playlist status bug
- timeslider not updated bug
- button/slider position and detection of button click is hardcoded

update the release documentation, only supported signatures are v3 signatures (gpg 2.x generates v3 sigs by default, but not gpg 1.x)

(FOSDEM is a great place)

if you need skins, use skins.
if you need skins and something else, use both.

workaround buggy alsa drivers

vlc.c: Attempt to kill VLC again if Ctrl-C is hit again when the abort timeout is ellapsed. It allows to abort VLC after the first abort timeout.

cmake: Add qt4 resources. Enable qt4 plugin compilation with cmake's CVS. (known not to work with cmake version 2.4-patch 7
)

Note that the format supported is the one created by FFmpeg, and not one of those described in the ticket.