TAJO-863: Column order mismatched in the JOIN query with asterisk selection. (Hyoungjun Kim via hyunsik)

Closes #31
TAJO-843: implements COALESCE for BOOLEAN, DATE, TIME, TIMESTAMP. (Hyoungjun Kim via hyunsik)

Closes #26
TAJO-860: Implements TRUNCATE table. (Hyoungjun Kim via hyunsik)
TAJO-860: Implements TRUNCATE table. (missed github closes)

Closes #29, #24.
Merge branch 'master' of https://git-wip-us.apache.org/repos/asf/tajo into TAJO-868

Conflicts:
	CHANGES