Had ExtKey start at 1 so KeyEvent.ExtKey can be 0.
Added the GTK+ implementation of Area keyboard events. Seems to work fine for now...
Fixed modifier keys in GTK+ not being registered by KeyEvent on first press.
Added GDK_KEY_Alt_L/R to the modifier key handling in GTK+ key events.
Added the tweets mentioned in one of the comments in area.go to the Area planning document.