This reverts commits 22b0995c and
dbdc867b.

RT::Authen::ExternalAuth is switching to ->Update as well, which lets us
use ->Update here without the waffling problem described by 22b0995c.
Using more core code is better.

Update method does s/\r\n/\n/g on values. This change
of values is not visible, but if combined with ExternalAuth
can result in regular change of a field back and forth.

It's not easy to exclude numeric users/groups with an LDAP filter,
leaving no way of acknowledging and suppressing the warning.  Rather
than add an option, just lower the log level.

While debugging it's helpful to see what was skipped, but under normal
usage (i.e. from cron), you want to ensure you see meaningful errors and
warnings not the same ones every night.

Filtering on (dn=...) is invalid because DN isn't an attribute.
Therefore if DN is what we need to search on, use the member's DN as the
search base and the standard user filter.  Only if we're searching on an
attribute do we now use the standard user base and an extended user
filter.

This lets you import a lot more of your LDAP information into RT, which
can be especially helpful with custom user/requestor displays on
tickets.

Note that the prefix is UserCF. not CF. as that's already used for
populating Custom Field Values (not _Object_ Custom Field Values).

Moved install instructions to INSTALL.

README is now generated from the pod via ReadmeFromPod.

Some more updates to pod in main file.

Added a feature to allow you to use a regex to match an LDAP member
field. But upon further review, I don't think it would ever be
needed unless someone's LDAP was really mis-configured. So this
commit is for posterity only.
(cherry picked from commit f5b2b5c7d0a02577f36782bebfdc5ff2082f9951)

Adds $LDAPSizeLimit which controls the page size requested by the
importer.  This lets us work with servers where the result set size
limit can't be increased.  If $LDAPSizeLimit is 0 or unset, no paging is used.

API change: _run_search now returns an array of Net::LDAP::Entry objects
instead of a Net::LDAP::Search object.

By default we still assume Member_Attr contains a list of user DNs.  If
you're running against OpenLDAP's default config, for instance, your
Member_Attr is memberUid which contains uids not DNs.  Member_Attr_Value
gives you a way to configure what value is matched against.

Refactors user caching for consistency.

This is in preparation for using cache keys other than DN.

Add an optimization for adding new groups; if we just created it, we know it is empty, so skip the member query

It really only stops Create from being called if the value is true

We don't handle nested groups, and if LDAP is flat and only lists
users in the parent group, we'll try and fail to remove the recursively
found users from the RT group, rather than removing the nested group.