schema engine updated (but not schema routines so things don't run yet)
nvalues mostly populated, enough for tests 0-2 to pass
schema routines needs lots of work
modify/mods codes needs lots of work
to back-bdb, back-ldbm and back-sql (the latter with limitations);
- added handling of ":dn" attributes to extended rfc2254 filters
and to matched value filter
- altered the behavior of get_mra() when a matching rule is given:
now it checks whether it is compatible with the attribute syntax
and, in case it is, the given mr is used. In case of no type,
the check is delayed when filtering
Changed AttributeDescription.{ad_cname,ad_lang} to struct berval everywhere
Deleted ad_free() everywhere
Added ad_mutex to init.c
The AttributeDescriptions are in a linked list hanging off of the
corresponding AttributeType.
