Node-ext-ldap

------------------

- Do not catch ``ValueError`` in
``node.ext.ldap._node.LDAPStorage.batched_search``.
[rnix]

- Use property decorators for ``node.ext.ldap._node.LDAPStorage.changed``
and ``node.ext.ldap.session.LDAPSession.baseDN``.
[rnix]

- Fix signature of ``node.ext.ldap.interfaces.ILDAPStorage.search`` to match
the actual implementation in ``node.ext.ldap._node.LDAPStorage.search``.
[rnix]

- Fix signature of ``node.ext.ldap.ugm.LDAPPrincipals.search`` according to
``node.ext.ugm.interfaces.IPrincipals.search``. The implementation exposed
LDAP related arguments and has been renamed to ``raw_search``.
[rnix]

- Add ``exists`` property to ``LDAPStorage``.
[rnix]

- Add ``objectSid`` and ``objectGUID`` from Active Directory schema to
``properties.BINARY_DEFAULTS``.
[rnix]

- Fix default value of ``LDAPStorage._multivalued_attributes`` and
``LDAPStorage._binary_attributes``.
[rnix]

------------------

- Switch to use mdb as default db for slapd i testing layer.
[jensens]

- fix tests, where output order could be random.
[jensens]

------------------

- make db-type in test layer configurable
[jensens]

------------------

- Turning referrals off to fix problems with MS AD if it contains aliases.
[alexsielicki]

- Fix search to check list of binary attributes directly from the root node
data (not from attr behavior) to avoid unnecessarily initializing attribute
behavior just a simple search
[datakurre]

- Fix to skip group DNs outside the base DN to allow users' memberOf
attribute contain groups outside the group base DN
[datakurre]

------------------

- Add a ``batched_search`` generator function, which do the actual batching for us.
Use this function internally too.
[jensens, rnix]

- In testing set size_limit to 3 in ``slapd.conf`` in order to catch problems with batching.
[jensens, rnix]

- Fix missing paging in UGM group mapping method ``member_ids``.
[jensens]

------------------

- Minor code cleanup
[jensens]

- Paginate LDAP node ``__iter__``.
[jensens, rnix]