ACCUMULO-1218 Overview on how to recover an instance from failed zookeepers

Ample warning given to the reintroduction of stale data (from files
that should be deleted but have not yet been deleted) or omission
of new data only present in WALs.
Merge branch '1.6.0-SNAPSHOT'
ACCUMULO-2503 fix time zone assertion
Merge branch '1.6.0-SNAPSHOT'