TAJO-1102: Self-join with a partitioned table returns wrong result data.

Closes #189
TAJO-1099: LogicalPlanner::convertDataType causes NPE in some cases.

Closes #185
TAJO-1104: Using asterisk with GROUP BY causes NPE.

Closes #187
TAJO-1021: Remove the member variable Builder from all classes inherited from ProtoObject.

Closes #188