Linux/Win disable screensaver using VLC

VLC will disable the screensaver during playback. This patch
exploits this functionality bringing it in line with the Mac
builds.

One small nit remains; under Windows/Linux the screensaver
is only disabled if video playback is being used, whilst on
the Mac the screensaver is disabled whenever you are active
(e.g. on a basic workout or streetview).

src/VideoWindow.cpp

@@ -32,6 +32,7 @@ GcWindow(parent), home(home), main(parent)
     const char * const vlc_args[] = {
                     "-I", "dummy", /* Don't use any interface */
                     "--ignore-config", /* Don't use VLC's config */
+                    "--disable-screensaver", /* disable screensaver during playback */
 #ifdef Q_OS_LINUX
                     "--no-xlib", // avoid xlib thread error messages
 #endif