for further mucking with data.  This can be of use in ill situations
where not all the required massaging can be done on data with SQL
by means of stored procedures, but overlays are called too early
and cannot be used to make data non LDAP compliant.
- only support for bidirectional DN mucking is provided right now
- support for other values mucking is planned
- write is not completely tested yet
- the API could change quite often; don't rely too much on it

other cleanup has been added.

Add better approx test

honor sizelimit requests on the overall count when pagedResults control is used; cleanup and more features

improve previous commit; now special limit on the number of total entries of a paged results can be set via the limits.  Need to decide whether the default should be unlimited or what

But without permissive.  That needs to be reworked completely.

- There might be special cases that require the unique key to be a string
  (just ran into one); since this is not a generally useful change, it's
  hidden behind #defines.
- Added essential support for telephoneNumber match; the same infrastructure
  might be useful for other specialized matches (also regular matches should
  use it to handle multiple spaces and so!).
- Fixed dynamic backend initialization.
- Cleaned up search base DN normalization (works also if no uppercase function
  is available, using case exact matches).