Remove DICT-GET-ERROR call from DICT-CHECK

enchant_dict_check() returns a negative integer if there was an error.
It's not certain that enchant_dict_get_error() will help describing the
error so don't call it automatically. At least UTF-8 encoding error
messages can be requested with DICT-GET-ERROR function. That function
will be exported in the following commit(s).
Export DICT-GET-ERROR function and update its doc string
Add BROKER-GET-ERROR function
Add BROKER-SET-ORDERING function
Move more BROKER-FREE-DICT code to FREE-FOREIGN-RESOURCE method