support for AD primary groups

support for primary groups

actually the problem is only known on AD, it is only needed to take care of their attributes

adjust to ADs special behaviour

this change was not intended

cache the SID value so it is not requested over and over again

theres only one, use singular

we are access

add tests for new Access methods

add tests for new Group methods

address scrutinizer findings, mostly doc

call ldap_explode_dn from ldap wrapper, enables tests without php5-ldap

PHP Doc

yo dawg, i heard you like backslashes … php doc fix

PHPDoc updated and typos fixed while reviewing
Merge pull request #9385 from owncloud/fix-7052

support for AD primary groups