TAJO-995: HiveMetaStoreClient wrapper should retry the connection. (jinho)

Closes #108
TAJO-1001: Add missed postgresql license to NOTICE.txt and LICENSE.txt.

Closes #114
TAJO-895: ConstEval should not be included in target list of projectable nodes.

Closes #111
TAJO-1000: TextDatum.asChar() is incorrect, if client charset is different. (jinho)
TAJO-1006: Fix wrong storage unit for kilo bytes and others.

Closes #117
TAJO-985: Client API should be non-blocking. (jinho)
TAJO-1007: Update site for new committer and new contributors.

Closes #120
TAJO-1009: A binary eval for column references of the same tables should not be recognized as a join condition.

Closes #121
TAJO-984: Improve the default data type handling in RowStoreUtil. (jihoon via hyunsik)
TAJO-1011: EvalTreeUtil::isJoinQual need to handle other join conditions. (jaehwa)
TAJO-704: TajoMaster HA (jaehwa)
TAJO-1008: Protocol buffer De/Serialization for EvalNode.
TAJO-1013: a complex equality condition including columns of the same table is recognized as a join condition.

Closes #123
Revert "TAJO-1008: Protocol buffer De/Serialization for EvalNode."

This reverts commit 49d52553c5e4ef37a6af4605befbe36b0dd36c3c.
TAJO-1008: Protocol buffer De/Serialization for EvalNode.
Merge branch 'master' of https://git-wip-us.apache.org/repos/asf/tajo into TAJO-906

Conflicts:
	tajo-core/src/main/java/org/apache/tajo/engine/eval/EvalType.java
	tajo-core/src/main/java/org/apache/tajo/engine/eval/FunctionEval.java
	tajo-core/src/main/java/org/apache/tajo/engine/eval/SimpleEvalNodeVisitor.java
Fixed IntervalDatum bug.
Refactored classes.