TAJO-1157: Required Java version in tutorial doc needs to be updated.

Closes #230
TAJO-1149: Implement direct read of DelimitedTextFile. (jinho)

Closes #221
TAJO-1128: Implement a select box for database at web interface. (Jongyoung Park via hyunsik)

Closes #222
TAJO-1026: Implement Query history persistency manager.

Closes #179
TAJO-1162: to_char() returns "-00" second.

Closes #234
TAJO-1161: Remove joda time dependency from tajo-core. (Jihun Kang via hyunsik)

Closes #233
TAJO-1109: Separate SQL Statements from Catalog Stores. (Jihun Kang via hyunsik)

Closes #201
TAJO-1152: RawFile ByteBuffer should be reuse. (jinho)

Closes #224
TAJO-1151: Implement the ByteBuffer-based De/Serializer. (jinho)

Closes #228
TAJO-1156: Improve the comparison of timestamp and date types. (Jihun Kang via jihoon)

Closes #237
TAJO-1174: remove unnessary codes for blobdatum (DaeMyung Kang via hyunsik)
TAJO-1179: Integration tests in TravisCI are occasionally failed due to log size.

Closes #245
TAJO-1169: Some older version of OpenJDK 1.6 does not get default timezone id. (Jihun Kang via hyunsik)

Closes #239
TAJO-1177: Reduce the use of Sun proprietary API. (Jihun Kang via hyunsik)

Closes #243
TAJO-1172: Remove Trevni storage type and its related classes (DaeMyung Kang via hyunsik)

Closes #244
TAJO-1184: Upgrade netty-buffer to 4.0.24.Final. (jinho)

Closes #248
TAJO-1178: Some error messages for wrong JSON queries are not so much helpful. (Jaewoong Jung via jihoon)
TAJO-1195: Remove unused CachedDNSResolver Class. (DaeMyung Kang via jaehwa)

Closes #253
TAJO-1197: Unit test failed: unable to create new native thread. (jinho)

Closes #255
TAJO-1200: Invalid shuffle data of multiple worker in same server. (jinho)

Closes #259