Fix a bug when there is "ATTRIBUTE(ANY)".
support hash function for all data typies.
Aggregation now support group-by operator on any data typy. -_-
In iterator supports hash on any data type.
Equal Join supports join key under any data type. -_-
Exchange allows to partition the data based on attribute under any data
type.
Add a method to create a projection containing all attributes.
Bugs have been fixed!
add assert in NValue to detect the overflow.
Before merging with li's master