OAK-90 : Implement Principal Management (fix visibility issue with PrincipalImpl)

git-svn-id: https://svn.apache.org/repos/asf/jackrabbit/oak/trunk@1471306 13f79535-47bb-0310-9956-ffa450edef68
javadoc

git-svn-id: https://svn.apache.org/repos/asf/jackrabbit/oak/trunk@1471307 13f79535-47bb-0310-9956-ffa450edef68
OAK-50 : Implement User Management  (minor improvement)

git-svn-id: https://svn.apache.org/repos/asf/jackrabbit/oak/trunk@1471309 13f79535-47bb-0310-9956-ffa450edef68