Added caveat to attr() function of jqLite

attr() does not support functions as parameters.

Author: cwclark

src/jqLite.js

@@ -39,7 +39,7 @@
  * - [`addClass()`](http://api.jquery.com/addClass/)
  * - [`after()`](http://api.jquery.com/after/)
  * - [`append()`](http://api.jquery.com/append/)
- * - [`attr()`](http://api.jquery.com/attr/)
+ * - [`attr()`](http://api.jquery.com/attr/) - Does not support functions as parameters
  * - [`bind()`](http://api.jquery.com/bind/) - Does not support namespaces, selectors or eventData
  * - [`children()`](http://api.jquery.com/children/) - Does not support selectors
  * - [`clone()`](http://api.jquery.com/clone/)