Wired contextmenu / toolbar events

Events from the context menu or toolbar trigger the
$.jstree.context[Event] functio.ns. Create menu now shows the vakata
context menu. Enabled copy and paste.
Added hotkey overrides to select rather than hover on arrow keys
Fixed undefined bug
Fixed copy and paste bugs

Added "pos" arg to paste so we can control the position. There seems to
be some confusion with par and new_par in the core plugin. I've changed
the callback function to send the parent instead of the new_parent to
the delta updates so the copy goes through correctly.
Enabled cut_node
Fixed cut bug

Hack to fix the cut node bug - issue is again the wrong parent sent on
callback
Fixed hotkeys last node left/right key bug, and refactored functions