Add recursive_group_search_fallback option

This lets us disable the fallback recursive group search when
virtual attributes aren't enabled. This may be necessary for large
directories that don't support virtual attributes due to performance
issues.
Avoid recursive group search when not enabled
Fix for change in group_filter signature
Merge pull request #31 from github/recursive-group-search-fallback-disable-option

Add recursive_group_search_fallback option
Make member_filter method take a Net::LDAP::Entry

This is in order to update it to filter by DN and CN.
Include memberUid=CN in member_filter
Add test for posixGroup handling for Domain#is_member?
Disable base domain LDIF entries

Fixes 'entry already exists' failures when booting ApacheDS.
Assert all members instead of first

Makes this test more consistent since the results could be in
different order each query, resulting in intermittent failures.
require -> require_relative for tests

Makes it easier to run tests individually.
Handle Net::LDAP::Entry[] returning an Array, filter nesting

Since moving away from "entry.dn" to "entry['memberUid']", the filter
value was changing and breaking the filter generated.

Also, Net::LDAP::Filter can't handle generating a filter with more than
two filter conditions (aka "(|(one)(two)(three))"), so account for that.
Exclude memberUid members from Group#members

This explicitness prevents breaking behavior when calling super
for PosixGroup#members.

Not all membership names are created equal, it seems.
Test posixGroup with/out recursive fallback

Since this exercises two different code paths and needs
full test coverage.
Define posixGroup fixture data, schema
Use custom schema for posixGroup tests
:fire: the commented-out organizations in LDIF fixtures
Merge pull request #34 from github/fix-entry-already-exists-error

Fix tests due to "entry already exists" error for the base domain
Merge branch 'master' into posixGroup-membership
:fire: a bit more
Match memberUid to configured uid field

Reverts changes to memebership names, favoring explicit filter conditions.