Contacts API updates

I've updated the Contacts draft in line with recent discussions.

As usual, the CVS log is available at [1] and changes from the previous
version can be viewed via the diff log at [2].

Please let me know if there are any outstanding changes to be made and
thanks for all your input to date.

- Rich

[1] http://dev.w3.org/cvsweb/2009/dap/contacts/Overview.html
[2]
http://dev.w3.org/cvsweb/2009/dap/contacts/Overview.html.diff?r1=1.98&r2=1.99&f=h