OAK-619 Lock-free MongoMK implementation
- Add check for updates of unsavedLastRevisions map
- Do not use regular commit mechanism for update of _lastRev

git-svn-id: https://svn.apache.org/repos/asf/jackrabbit/oak/trunk@1466392 13f79535-47bb-0310-9956-ffa450edef68
OAK-746 Builder for the MongoMK

git-svn-id: https://svn.apache.org/repos/asf/jackrabbit/oak/trunk@1466393 13f79535-47bb-0310-9956-ffa450edef68