Add raw IP decoding to Peer creation

In the style of the "pnSeed" array in Bitcoin reference client; probably defined in source by a hex-string, but therefore input into the function as a number.
More robust host definitions

If no 'host' value is defined, default to 'localhost', and a colon-delimited port in a host string overrides an explicit port argument.
Allow binding to an open socket

Add an argument to the connect() method, for an already-opened socket. This will be needed for dealing with new connections discovered by listening on an open port for remote-initiated connections.