Having a command to bounce a REPL would be helpful, since it's a common thing to do during clojure development.

Related: add a command to kill a REPL. Without this, it won't be clear to most users how to kill the underlying JVM that inf-clojure starts -- I don't believe killing the *inf-clojure* buffer does it.

This interactive command (or one of its helper functions) should take as a parameter the buffer who's REPL should be stopped/restarted, for ease of scripting multi-REPL workflows.