Disabling numberDisplayed is broken since 0.9.14

[l3ehnam]

Setting numberDisplayed to 0 doesn't disable this functionality since 0.9.14

$(document).ready(function() {
	$('#example-numberDisplayed').multiselect({
		numberDisplayed: 0
	});
});

[AdrianHL]

I have experienced the same issue today while first using this amazing package. Here is a PR that fix the issue #1039. Thanks