Replaced jetty with http-kit.

Reasons:
- No double logging mechanism (jetty uses a different logger).
- Smaller artifact.
- Just for fun :)
Fix remote repl where clojure.repl not loaded.

This can usually happen when connecting to remote nrepl server that are
on production mode.
Version 0.4.3!
Merge branch 'release/0.4.3' into develop