tweak handling under iOS

Author: zeitiger

src/selectize.js

@@ -1745,6 +1745,7 @@ $.extend(Selectize.prototype, {
 
 		self.isOpen = false;
 		self.$dropdown.hide();
+		self.$control_input.blur(); // close keyboard on iOS
 		self.setActiveOption(null);
 		self.refreshState();