Update to Rails 4.1

Other noteworthy changes:

  * Removed the unused UsersController and references to OmniAuth which
    were raising errors.

  * shoulda-matchers no longer required in the Gemfile, since doing so
    outputs messages about minitest.

  * Default scope removed from Scenario, and added it explicity to the
    few places which need it.

  * Admin actions now use strong_parameters since attr_accessible has
    been removed in Rails 4.1.

  * Fixed bad indentation in the Tour coffee file which prevented
    compilation in the newer version of CS.

  * Updated Haml from 3.1 to 4.0.

  * Updated simple_form from 2.1 to 3.0.
Merge pull request #415 from quintel/rails-4.1

Update ETFlex to Rails 4.1
Fix when a user enter a name longer than 50 characters
Gedaan -> Klaar
Add some useful "feature" classes to the <html> el

Allows CSS to know what features are enabled and adjust the styles to
compensate.
Disable scores for the session with the query string

On the root page, or a scenario page ("modern" or "house"), include the
"scores" parameter in the URL to set whether to display the high score
podium and high score list.

To disable scores, any of the following will work:

  * scores=off
  * scores=no
  * scores=false
  * scores=hide

Any other value will turn scores back on.

For example:

  * http://beta.etflex.et-model.com/?scores=off
  * http://beta.etflex.et-model.com/?scores=on
  * http://beta.etflex.et-model.com/scenes/1/with/348179?scores=hide

Closes #418.
Disabling scores also removes them from the root page

Ref #418
Improve spacing around sponsor when scores are off
Add "treat symbols as metadata" option to spec_helper
Ensure user and guest names don't exceed 50 chars
Set guest name with a "who" parameter

Including a "who=something" query param, you may now set the name of the
current guest user.

If the user had an active session already, we simply set the guest name
so long as they haven't already entered one. If the session has a guest
name already, we create a new session and set the name.

For example:

  http://beta.etflex.et-model.com/?who=Jeff
  http://beta.etflex.et-model.com/scenes/1?who=Britta

Closes #419.
Document the "scores" and "who" options
Add space between the house and the dashboard
Zoom dashboard props when the value changes

Ref #420
Update to Rails 4.1.5
Update Capistrano to version 3