Proposal to add ldap flexability in DIT layout

[Shahms E. King]

One of the early patches actually had this separation, or at least early
attempts at it for exactly those reasons, however it was removed very
quickly after trying to actually get it working in a number of places. 
At first glance it looks straightforward, but there are a few places
where lookups are done, and determining which base to search resulted in
either large-scale code duplication or just plain ugly code, and I was
more concerned with getting LDAP support working (and cleanly) at the
time than adding things like that. Now that LDAP seems to have
stabilized, it shouldn't be too difficult to add the necessary bits,
though.

--Shahms