add a version of sticky modifier keys that doesn't lock

i like OS X's built in sticky key support, but i don't like the lock feature, and i'm not the only one:

http://apple.stackexchange.com/questions/13708/disabling-the-keep-pressed-function-of-os-x-sticky-keys

this adds a sticky keys option that doesn't lock. i took a guess at where it would fit, but feel free to move it anywhere else. thanks in advance!