HBASE-11349 [Thrift] support authentication/impersonation
HBASE-11349 Addendum fixes javadoc warning
HBASE-11481 TableSnapshotInputFormat javadoc wrongly claims HBase 'enforces security'
HBASE-11444 Remove use of reflection for User#getShortName
HBASE-11088 Support Visibility Expression Deletes in Shell (Ram)
Merge remote-tracking branch 'remotes/origin/0.98' into 0.98