#49 [Req 103] Capability to add constraints in abstractionDefini

[Mukesh Chopra]

Bus/Abstraction Definitions represents protocols and these protocols may have typical rules also associated with them e.g.
- width of data bus can be 8,16,32 or 64
- address bus width is depedent on width of data

The idea is to be able to capture all such information in the abstractionDefinition,so that a check against these can be done for the IP-XACT view of the IP adding more robustness to IP-XACT based design techniques