Adjust inputBindings keyset so that it can be overlaid with platformGlobalOverlay.xul. Rewrite emacs keybindings in the unix overlay to track mjudge's latest changes. r=mjudge, a=jar git-svn-id: svn://10.0.0.236/trunk@55890 18797224-902f-48f8-a5cc-f745e15eee43