Add support for Finagle HTTP servers

This pull request adds preliminary support for Finagle HTTP. It provides constructors and Clojure-friendly wrappers for `Server`, `Request`, and `Response` objects, and basic `ServerBuilder` support. It does not yet attempt to wrap all possible getters and setters.
does this need to be closed after the test runs? otherwise successive runs through `lein midje :autotest` will fail since the port will already be bound