Extends Arte.Text area to add undo/redo capabilities
The undo manager exposes the following public api to the Arte Text Area
Perform an undo action
$(".editor").Arte.undo();
Perform an redo action
$(".editor").Arte.redo();
Whether or not the manager can undo (is there an undo on the stack)
var hasUndo = $(".editor").Arte.hasUndo();
Whether or not the manager can redo (is there a redo on the stack)
var hasRedo = $(".editor").Arte.hasRedo();