Added Conds interface

Added interface to represent conditions in a query.
Also the basic implementation of it.
Update ListCond and Service interface

1. Added the new Conds as a parameter in BasicListCond.
2. Added method GetCond in ListCond so it can return generic query condition.
3. Added method GetMap in ListCond so it can work better with upperio.
4. Change Service.List to a generic listing method.
5. Renamed original Service.List to Service.ListChildren.
Implement the new Service interface in upperio

Midified upperio.Service to implement the new interface.