Duplicate signing

[Cantor, Scott]

This is checked in and added to all the flows.

I realized there's really only one correct approach, we should just use Predicate<MessageContext> whereever that's appropriate, and then if we need a Predicate<ProfileRequestContext> we should build that adapter (and have it specify INBOUND or OUTBOUND). Otherwise we'd have to build the inbound/outbound flag into every one of these predicates anyway.

-- Scott