Merge remote-tracking branch 'upstream/motion' into motion

* upstream/motion:
  Sort countries, tutorial on 1st launch
  Fix european union flag
  Display initial help in propositions view controller
  Add content for tutorial
  Add tutorial with UIPageViewController
  Add HelperViewController
  Add country flags and spinner
  Fix tags table view row height
  Only display back button when needed
  Simplify election selection
  Choose election
  Update rakefile & TestFlight config (without tokens)
  Button with voxe logo
  Update tags tableview
  Update gitignore
  Logs and formatting
  Add icons to tags