Controlgroup: Don't use String.prototype.trim()

We still support IE 8, which doesn't have this method.

Author: scottgonzalez

ui/widgets/controlgroup.js

@@ -234,7 +234,7 @@ return $.widget( "ui.controlgroup", {
 		var result = {};
 		$.each( classes, function( key ) {
 			var current = instance.options.classes[ key ] || "";
-			current = current.replace( controlgroupCornerRegex, "" ).trim();
+			current = $.trim( current.replace( controlgroupCornerRegex, "" ) );
 			result[ key ] = ( current + " " + classes[ key ] ).replace( /\s+/g, " " );
 		} );
 		return result;