TAJO-244: assignToNonLeafTasks causes NPE occurs occasionally . (hyunsik)
TAJO-243: The 'tajo_dump' does not include options of table. (jinho)
TAJO-245: org.apache.tajo.algebra.FunctionExpr cannot be cast to org.apache.tajo.algebra.ColumnReferenceExpr. (hyunsik)
TAJO-250: QueryMaster must send the query finish heartbeat. (hyunsik)