Message can have multiple contact entries

[vodik]

trafficstars

We probably need to rethink contact_details attribute on messages as its completely valid to have multiple Contact headers.

For example, from RFC 3261 on registrations:

If more than one Contact is sent in a REGISTER request, the registering UA intends to associate all of the URIs in these Contact header field values with the address-of-record present in the To field. This list can be prioritized with the "q" parameter in the Contact header field. The "q" parameter indicates a relative preference for the particular Contact header field value compared to other bindings for this address-of-record. Section 16.6 describes how a proxy server uses this preference indication.