drop javascript altogether. latest coffeescript executable can provide
backtraces in *.coffee format; so now its all coffee all the time :)
- latest coffee executable works with node-inspector; using that, instead
- avoid killing ALL node processes; instead kill ANY process(es)
  listening on the debugging ports. usually this is only a specific node
  instance, but makes absolutely sure, and doesn't kill unrelated
  friendly node processes which may already be running in background.
- auto-launch new chrome browser/tab for convenience
- fix typo for some bash versions