Allow to switch to fullscreen mode using LIRC.

Allow to switch to fullscreen mode using LIRC.

Imagine the following situation (which happened to me several times) :
you want to see photos from your bed or your sofa so you launch geeqie
and go to the right directory, then you take your remote control and sit
comfortably far from your keyboard and mouse. And when you want to begin
to watch photos, you realize you forgot to enable full screen! You have
to stand up and to go until your computer and come back, whereas you
could have done it with your remote control.

Patch by Bernard Massot.