Adds qtranslate support

if QTRANS_INIT is defined and the function qtrans_getLanguage() exists adds a MC_LANGUAGE merge var to populate language preference

```php
  if ( defined('QTRANS_INIT') && function_exists('qtrans_getLanguage') ) {
    $lang = qtrans_getLanguage();
    $merge['MC_LANGUAGE'] = $lang;
  }
```