[fix] is_valid_lang fixed for new languages.py + dictzone engine encoding

searx/engines/dictzone.py

 
     params['url'] = url.format(from_lang=from_lang[2],
                                to_lang=to_lang[2],
-                               query=query)
+                               query=query.decode('utf-8'))
 
     return params
 

searx/utils.py

     if is_abbr:
         for l in language_codes:
             if l[0][:2] == lang.lower():
-                return (True, l[0][:2], l[1].lower())
+                return (True, l[0][:2], l[3].lower())
         return False
     else:
         for l in language_codes:
             if l[1].lower() == lang.lower():
-                return (True, l[0][:2], l[1].lower())
+                return (True, l[0][:2], l[3].lower())
         return False