Optional settings file

Hey Zendesk,

I added functionality to support a settings YAML file instead of repeatedly asking to fill out all the settings on startup. For bigger apps with lots of settings this can get very annoying.

- It expects a settings.yml file a directory higher than where app.js is located.
- It doesn’t fail, but just gives you the normal prompt if an error occurs.
- TOO: We could add checking for required settings, if that setting isn’t in the settings.yml file.

What do you guys think?
Olaf