fix repl completion and navigation
fix repl completion and navigation

The readline interface of node has changed in [aad12d0][] and because of
that the autocompletion and key movement didn't work anymore. This
commit fixes this by checking whether stdin is in raw mode (i.e. invoked
as a script) or not (as a repl).

[aad12d0]: https://github.com/joyent/node/commit/aad12d0

sterpe/coffee-fmt