[sv-cc] proposal for item# 606 uploaded

Proposal for item# 606 (clocking block) has been uploaded.
I have incorporated all suggestions in the mantis item.

Also I found that the property vpiDefaultSkew on clcoking io decl
is ambiguous. A clocking io decl can have 2 skews, input and output.
Either one of them or both can pick up default skews according to the LRM.
When one of the skew is default and the other one not, having a single
property (vpiDefaultSkew) is doesn't suffice and can't return the complete
information. Moreover I think the default skew is some kind of a syntactic
sugar (short hand to write clocking block) in the language and has no
real symantic difference compared to non-default skew.
I proposed that this property be removed from clocking io decl.
Comments are welcome.

regards,
-sachi