Improve hotkey handler
Improve hotkey handler

Better keycode support
Ignore hotkeys in form fields

R=jeff.pihach, benji
CC=
https://codereview.appspot.com/9906044

CanonicalJS/juju-gui,CanonicalJS/juju-gui,CanonicalJS/juju-gui,mitechie/juju-gui,jrwren/juju-gui,jrwren/juju-gui,bac/juju-gui,bac/juju-gui,mitechie/juju-gui,jrwren/juju-gui,jrwren/juju-gui,mitechie/juju-gui,bac/juju-gui,bac/juju-gui,mitechie/juju-gui