TAJO-1028: JDBC should support SET command.

Closes #135
TAJO-1029: TAJO_PULLSERVER_STANDALONE should be false in default tajo-env.sh. (jinho)

Closes #134
TAJO-1022: tsql does not work as background process

Closes #128
TAJO-1027: Upgrade Hive to 0.13.0 and 0.13.1. (jaehwa)
TAJO-1038: Remove use of Builder variable in Schema.

Closes #140
TAJO-1034: Reduce Explicit Use of JVM Internal Class. (Jihun Kang via hyunsik)
TAJO-1024: RpcConnectionPool::getConnection can cause NPE at initialization.

Closes #139
Merge branch 'master' of https://git-wip-us.apache.org/repos/asf/tajo into EliminateDatum
Improved TupleComparator.
Improved CSVFileScanner and TupleComparator.
Fixed some bugs.