Removed unused OCluster.lock and unlock methods + exception on setting unsupported changes to clusters
Merge branch 'develop' of https://github.com/orientechnologies/orientdb into develop
Issue #1604 ridset works only in embedded mode.
Merge branch 'develop' of https://github.com/orientechnologies/orientdb into develop
1. MVRBtreeRid  reformatting.
2. JDK 6 compatibility fix.