TAJO-1001: Add missed postgresql license to NOTICE.txt and LICENSE.txt.

Closes #114
TAJO-895: ConstEval should not be included in target list of projectable nodes.

Closes #111
TAJO-1000: TextDatum.asChar() is incorrect, if client charset is different. (jinho)
TAJO-1006: Fix wrong storage unit for kilo bytes and others.

Closes #117
Merge branch 'master' of https://git-wip-us.apache.org/repos/asf/tajo into TAJO-704
Added TajoHAClientUtil.