Keyboard Support

Enables Keyboard support when in picker mode and not in picker mode

1. When picker launches, auto-selects first button using focus()
2. Pressing TAB navigates will wrap in the picker
3. Pressing ESC on a selected node will close the picker and not select anything
4. Pressing ENTER on a selection option will select that like a mouse click would in PICKER and NON-PICKER mode.

There is one defect I commented with a FIXME that I am working on, it has to do with auto-focusing $icon after performing a hidePicker, ESC is bubbling up to my bootstrap modal and i've not fixed that yet.