fullcalendar can now be initialized with no options (issue 1356)

src/main.js

@@ -27,7 +27,8 @@ $.fn.fullCalendar = function(options) {
 		}
 		return this;
 	}
-	
+
+	options = options || {};
 	
 	// would like to have this logic in EventManager, but needs to happen before options are recursively extended
 	var eventSources = options.eventSources || [];