TAJO-332: Invalid row count of CSVScanner. (jinho)
TAJO-308: Implement length(string) function. (hyoungjunkim via hyunsik)
TAJO-279: Improving the query_executor page of web UI. (Wan Heo via jihoon)
Completed distinct.
TAJO-290: TajoDataType.Type.NULL should be NULL_TYPE. (DaeMyung Kang via jinho)
Almost completed. Only remain union handling.
Merge branch 'master' of https://git-wip-us.apache.org/repos/asf/incubator-tajo into OUTER_JOIN