[code_exs] Updated the routing for the examples to use app.js, not routes.json.

The only examples that still attach routes from `routes.json` were those that used the Url addon, which requires the `routes.json`.  Some errors were also fixed in the dashboard module apps, which are not tested. 

Note: the `app.js` for each example has the line `app.mojito.attachRoutes();` commented out with a note about what it does and that `routes.json` has been deprecated.