Fixed JavaScript error while typing in chrome

Regression from 8c8b02f for #36.
Fixed JavaScript error typing in chrome

Regression from d88697a.
Toggle on double Ctrl

Adopted the more comfortable key chord in AVIM for Chrome. Key chord handling is per window and can be canceled by typing or clicking anywhere in the window, or by pressing a key in combination with Ctrl. Fixes #35.
Minify CSS w/ cssmin

The strip-all-whitespace regex just happened to work until now, but it doesn’t like :-moz-any() at all.
Fade in red strike-through

Easier to notice that way.
Show double Ctrl key chord in menu

It isn’t a formal keyboard shortcut, so this change uses some clever CSS to stick a gloss in the usual spot.
Play a faint cue when toggling via double Ctrl

It’s very easy to hit Ctrl twice w/o thinking about AVIM. A faint cue alerts the user that something has changed. This change uses notfound.wav, a sound built into Toolkit that used to be used for Find As You Type.
Updated CHANGELOG