contrib/microevent.js -- trigger() may reference undefined property

[rotdrop]

I ran in a small problem when destroying the selectize instance an an on-change event handler. The reason is that

selectize.js/src/contrib/microevent.js

Lines 27 to 33 in 3c4d241

	trigger: function(event /* , args... */){
	this._events = this._events || {};
	if (event in this._events === false) return;
	for (var i = 0; i < this._events[event].length; i++){
	this._events[event][i].apply(this, Array.prototype.slice.call(arguments, 1));
	}
	}

does not handle the case when the event-handler destroys the "this" object. In this case the "this" object is still there (as it is still referenced here), but its _events property is gone. See pull request #1855.