Initial version of the socket server and R bindings.
Example pared down.
Basic socket server is working. Note that it blocks on next_request.
We may need to switch to an asynchronous acceptor and add a timeout
on next_reqest (and/or signal handler).
Service example is working with the new asio socket server.
Merge pull request #3 from kaneplusplus/master

Proper socket server for rrest