Does the libbitcoin project provide any ABI or API stability
guarantees at this point? Up to now, all my changes have been
backwards-compatible additions. Now, however, I would like to make a
few breaking API changes to the obelisk client library.

Specifically, I am trying to use zeromq to communicate between
elements of my own program, but the zmq_context object is hidden
inside the fullnode_interface object. This is bad, since zeromq
context is something that needs to be created on the outside and
passed in.

Also, the polling methodology used in the client library is... not so
good. In the current system, the update() method needs to be called on
a regular basis, like once every 10 seconds, to check for new
messages. This is inefficient and wrong. The right way to do it is to
have the main loop sleep on the incoming sockets, waking up only when
activity occurs. Fixing this will involve somehow exposing the zeromq
sockets to the client code. We are a mobile app, so this sort of thing
matters to us for battery life.

-William