Fallback to direct initiate when no Jingle Message Initation support

Check for a message initiation supporting resource, if none then send to the
most available resource.

TODO: Should only send to most available resource that supports jingle rtp audio.

Initial commit

This code is garbage and will have to be rewritten.

When paired with the Asterisk setup, inbound calls to sip:some%40jid@server.tld
end up as working Jingle calls (tested only with Conversations) to the target
JID.

Declining the call, hanging up, and errors from calling bad JIDs all are handled.