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 merging with Li's master
test for push
Merge branch 'fzu' into ExpandableFramework

Conflicts:
	Test/TestMain.cpp
	ids.h
fixed error caused by last merge
Expandable framework seems to work~ -_-.
Fixed a bug in aggregation caused by partially lock.
add proper const property to some methods.
Add property const properties to some methods.
support lock and unlock on a given hash bucket.
Add context structure and related access methods.
Currently, the context contains the block for asking and its iterator.
Expanded thread can be created and dropped on demands. Context has been
integrated into Filter.
Expandable Scan and Filter currently well support threading expanding
and thread shrinking
Expandable aggregation and join can expand and thresh thread at any time
during the execution.
Create Readme.me
checkpoint