Remove automatically added duplicate keywords and cut the resulting string

The module does not remove duplicates of taxonomy/default/global tags, automatically included by 'Extra functionality' submdule. Furthermore, resulting string is not limited by Default maximum length setting.
So I suggest the solution:

Edit metatags_quick_extra.module
After string
$keywords = array_merge($node_keywords, $taxonomy_keywords, $default_keywords, $global_keywords);
add

      foreach ($keywords as $key => $value) {
        $trimmed[] = trim($value);
      }
      $keywords = array_intersect_key($trimmed,array_unique(array_map('strtolower',$trimmed)));
      $keywords_content=implode(',',$keywords);

      $maxlen=variable_get('metatags_quick_default_field_length');
      if($maxlen>0 && strlen($keywords_content)>$maxlen){
        $keywords_content_cut = mb_substr($keywords_content,0,$maxlen);
        if($keywords_content[$maxlen]!=',')$keywords_content_cut = mb_substr($keywords_content_cut,0,mb_strrpos($keywords_content_cut, ','));
        $keywords_content = $keywords_content_cut;
      }

Then find 2 occurrences of implode(',',$keywords) and replace by $keywords_content