code: function() {
  			this._commitUndo();
  			var changes = [];
  			for (var i=this.index; i >= 0; i--) {
  				changes = changes.concat(this.stack[i].getUndoChanges());
  			}
  			return changes;
  		}
docs: Returns the undo changes.
  
  @return {orion.editor.TextChange[]} an array of TextChanges that are returned in the reverse order
  that they occurred (most recent change first).
  
  @see orion.editor.UndoStack#getRedoChanges