Several presentation remotes (mainly Logitech and its cheaper clones) send
Shift+F5 as a combination for entering presentation mode. Evince does not
currently react to Shift+F5; this patch fixes that.

In Powerpoint, Shift+F5 starts a presentation from the active (current) slide,
whereas F5 starts the presentation from the beginning.

Either way, it is expected that remote controls send either key stroke.