[RP] caps lock, numlock and scroll lock ignored

[shawn]

So something that has been annoying people for some time now is rp not
responding when the capslock, numlock, or scroll lock is on. I've now
fixed this.

Something I noticed while doing this is that a prefix key can't be
uppercase or any key that requires you to press shift to get it and it
may not be able to be an AltGr'd key (haven't tested that one). But
there is little reason to set your prefix key to C-T or C-? or
something silly like that, so I think we can let it slide...