issue-#48: Use of trusted-anchor sub-option between Access Routers

The issue is that draft 07 requires use of the Trusted Anchor sub-option
between access routers for an AR to request its CAR to send certificates.
Typically an AR would be interested in obtaining certificate chains for all
trusted anchors possessed by the CAR, and since there is no logical
bandwidth limitation on the inter-router interface, there is no reason to
limit the number of certificates transmitted.

The suggested resolution is to include a flag in the CARD Request header for
the AR to indicate that it wants all the certificate chains.

            jak