update gantry to v4.1.21

### Bug

 * Notice: Undefined property: stdClass::$channel in j3 newsfeeds
 * Joomla 3.2 compatibility updates
 * Two factor authentication fields still present in login form even when two factor plugins are disabled
 * Default template version incorrect
 * Google Font don't display Variant
 * FontAwesome icon misalignment in some cases

### Improvement

 * Date language problem
 * Clear LESS cache when main cache is cleared.
 * Upgrade google analytics to use Universal Analytics code