Destroy instance of WYMeditor

wymeditor_destroy.js

/**
 * destroy instance of wymeditor:
 * - updates content between iframe and textarea
 * - remove iframe
 * - show textarea
 * - replace element with undefined (to trick jQuery.getWymeditorByTextarea(el)) 
 * @see https://github.com/wymeditor/wymeditor/blob/master/src/wymeditor/core.js#L520
 * @param {WYMeditor.editor} instance
 */
var wymeditor_destroy = function (instance) {
	instance.update();
	instance._box.remove(); 
	instance._element.show(); 
	instance._element[0] = undefined;
};