Fixes#899.
Before this commit, the dust threshold used to filter
orders in `jmdaemon.OrderbookWatch` was different than
that used in `jmclient`. This is corrected by setting
the threshold in client config and passing this as a
parameter in the `JMInit` command (since the daemon
does not know the client config).
Parse incoming and announce outgoing fidelity bond messages
Fidelity bond proof messages will be checked and added to the internal
database just like offers. Such messages are not announced in public
but only directly to takers who ask for them, this is because the
signature proofs must commmit to the maker's and taker's IRC nicknames
in order to avoid replay attacks.