all changes made by fzhedu since last merge.
Merge the changes made by fzhedu and zhanglei since May.27th.

Conflicts:
	BlockStreamIterator/ParallelBlockStreamIterator/BlockStreamAggregationIterator.cpp
	Test/TestMain.cpp
	Test/common/TestNew.cpp
	common/ExpressionItem.h
	common/Mapping.h
	common/Message.h
	common/Schema/Schema.cpp
	common/Schema/Schema.h
	common/TypeCast.h
	common/hashtable.cpp