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.
Fixed a bug when concurrently calling
Before mering with casa's code
Merge branch 'casa'

Conflicts:
	.cproject
	.project
	Test/TestMain.cpp
	common/ExpressionCalculator.cpp
	common/ExpressionCalculator.h
	common/ExpressionItem.cpp
	common/ExpressionItem.h
	common/Expression_item.cpp
	common/TypeCast.h
	common/functions.h