remove reduntant item
Merge branch 'Client & Server'

Conflicts:
	.gitignore
try to merge the data type codes contributed by dsc
data type promotion
a synchronizing point for zhuhe and kai
+ for arithmetic expression, < for compare expression,
CASE..WHEN..THEN..ELSE for composite function.
test utility
add setValue methods to ExpressionItem to facilite the intialization.
3-8
3-9
3-9 20.31
fzhehe's contribution
Merge remote branch 'wangli/master'

Conflicts:
	.cproject
	.gitignore
	BlockStreamIterator/BlockStreamPrint.cpp
	Parsetree/Test/parser_test.cpp
	Test/TestMain.cpp
before fetch li's branch
test
Before refine the codes in ExpandableAggregation
Before add Barrier Number into ExpandableBlockStreamIteratorBase
In the current version, theoretically, scan, filter, join, and
aggregation supports new expanded thread being added at any time during
the execution.
Before merging with Li's master
Before merging with My master branch