Keep client and server in separate namespaces

[technomancy]

Leiningen pulls in drawbridge for the purposes of connecting to a drawbridge repl as a client. I'd like to add an :exclusions entry for ring since it's not needed for our purposes, but then we won't be able to load the drawbridge namespace since the client and server are in the same place.

I can do a pull request that moves ring-client-transport into the cemerick.drawbridge.client namespace if you agree.

[technomancy]

Got a thumbs up in IRC.

[cemerick]

Merged, thanks! 0.0.4 pushed to clojars.