TAJO-1190: INSERT INTO to partition tables may cause NPE.

Closes #250
TAJO-1183: Keep command execution even with errors. (Jaewoong Jung via hyunsik)

Closes #266
TAJO-1222: DelimitedTextFile should be tolerant against parsing errors.

Closes #277
TAJO-1220: Implement createStatement() and setEscapeProcessing() in  JdbcConnection. (YeonSu Han via hyunsik)
TAJO-1223: Wrong query verification against asterisk and more expressions in select list.

Closes #279
TAJO-1224: When there is no projected columns, json scan can be hang.

Closes #281
Merge branch 'master' of http://git-wip-us.apache.org/repos/asf/tajo into index_support