Show alert if Clojure REPL fails to start
As per #35, the user will see an error message if something goes wrong while the REPL is starting, provided that the REPL manages to start eventually. If it doesn't, there's still no error message. We should display some sort of alert (like a yes-or-no-p or similar) in this situation.
Perhaps instead of opening the *cider-repl* buffer it could open the *nrepl-server* buffer, which would already have the error message.
A better solution to this problem would be to make it so that C-c M-j pops the *nrepl-server* buffer instantly, and then this buffer is replaced by the *cider-repl* buffer once the latter is ready.
We should make sure the resulting solution is compatible with C-c M-J as well.
Closing as stale: I no longer use Clojure, and nobody else has complained about this bug.