Consider adding more prompted options for cabin gruntfile generation
It might be nice to have some additional prompts when the user runs `cabin new` to allow for a better initial gruntfile.

Some end users might want a `dev` and a `dist` build for their site.  This is annoying to do by hand each time but really easy to make a gruntfile template for.

Other things that users might want:

Coffeescript compilation, image optimization
