cleanup
Add client user model and logout button
Add some styles from puavo
Close Lightbox on bg click
Fix logout route
style fix
Do not mutate test data

helpers.user.teacher is shared between all test cases.

@jpkorhonen
Reduce unnecessary promise nesting

@jpkorhonen
Do not ignore addFollower errors

Make sure that addFollower(...) is part of the promise chain
Handle errors from createOrUpdateUser

@jpkorhonen
Move createOrUpdateUser to the User model

Rename to ensureUserFromJWTToken and document it.
Simplify error handling with Function.prototype.bind

node.js style done callback expects an error as the first argument. Bind
the first argument to null to avoid false positive from the 'then'
callback.