REFACTOR+FEATURE: cleanup, new user gracefulness

- Made a new WelcomeView in the Activity controller
- Cleaned up the view creation the activity controller. Now, the
  templates are actually able to be used, unlike before.
- Added a new helper in lib (new-user-helper), which right now has a
  function isNewUser which does what you expect (boolean answer about
- whether a user is new). The threshold for the minimum reading amount
  required to not be a new user is set in `app/config.coffee` (not the
  other config!)