OAK-1915: TarMK failover 2.0

Added metatype descriptor.


git-svn-id: https://svn.apache.org/repos/asf/jackrabbit/oak/trunk@1625963 13f79535-47bb-0310-9956-ffa450edef68
OAK-1990: Utility js methods to manage Oak data in Mongo

Add function to print revision with human readable date

git-svn-id: https://svn.apache.org/repos/asf/jackrabbit/oak/trunk@1625995 13f79535-47bb-0310-9956-ffa450edef68
Merge remote-tracking branch 'upstream/trunk' into trunk