Allow several LDAP domains
PSR-2 compliant
LegacyLdapDriver still alive
Some fixes (legacy driver + doc)
Merge commit 'refs/pull/upstream/45' into 2.0.x

* commit 'refs/pull/upstream/45':
  Some fixes (legacy driver + doc)
  PSR-2 compliant LegacyLdapDriver still alive
  Allow several LDAP domains