TAJO-1040: Misuse netty HashedWheelTimer. (jinho)
TAJO-1048: Missed use of session variables in GlobalPlanner.

Closes #146
TAJO-948: 'INSERT INTO' statement to non existence table casuses NPE. (Jongyoung Park via hyunsik)

Closes #142
Merge branch 'master' of https://git-wip-us.apache.org/repos/asf/tajo into block_iteration

Conflicts:
	tajo-core/src/main/java/org/apache/tajo/worker/Task.java