ACCUMULO-1312 use Credentials object to avoid serializing as long as
possible
ACCUMULO-1312 Fix mapred and proxy serialization issues.
Merge remote-tracking branch 'asf/master' into ACCUMULO-802
Merge remote branch 'apache/master' into ACCUMULO-802
Merge remote branch 'ctubbsii/ACCUMULO-802' into ACCUMULO-802
ACCUMULO-802 renamed TableNamespacesTest to an integration test: TableNamespacesIT