Don't open Screenshot Manager if F3 is held.

Should allow uninterrupted use of the F3 debug keys no matter what the keybind is set to. (F3+H)
There's probably a way to do it so if the bound key isn't a debug key, it will open anyway.
Merge pull request #3 from killjoy1221/patch-1

Don't open Screenshot Manager if F3 is held.