OAK-709: Consider moving permission evaluation to the node state level
- implement rebasing of secure node state differences on top of non secure node state giving transient changes precedence: no need to override compareAgainstBaseState
- remove done TODOs

git-svn-id: https://svn.apache.org/repos/asf/jackrabbit/oak/trunk@1468820 13f79535-47bb-0310-9956-ffa450edef68