Simplified coffeescript code for the tour.
Added "show_mobile_tour" boolean flag to users. It defaults to true.
Reworked logs in User#default_values
Added unit test for the default value of the show_mobile_tour attribute of the User model.
Return the show_mobile_tour flag with the rest of user configurations via JSON.
Renamed the /api/tour_i18n.json route to /api/tours/show_main.json

This makes it easier to add routes to retrieve i18n strings for other tours, e.g. /api/tours/mobile.json