Copy change to make it easier for visitors to understand that they have not been given their
first choice of a slot.

[Finishes #79610480]
Display only start times of unsuccessful slots
Merge pull request #83 from ministryofjustice/copy-change-around-slots-79610480

Copy change to make it easier for visitors to understand that they have ...
Upgraded rails to 4.1.7.
Minor test fixes, unrelated to the upgrade.
Upgraded sass-rails.
Added another bad domain.
* Generated a controller for entering visitor information in the API flow.

[#81200736]
* Added a switch for displaying a phone number input in different flows.

[#81200736]
* Moved common templates to another location.

[#81200736]
* Added a flag for instant booking.

[#81200736]
* Some tests.
* Branch to the API flow unconditionally if the prison supports it.

[#81200736]
* Moved common visitor-related functionality to a separate module.
* DRY-ed up tests, so that parts are reusable across both flows.

[#81200736]
* Separated models into deferred- and instant-.
* DRY-ed tests around models.

[#81200736]
* VisitorsManipulator now knows which model to manipulate, and can be reused across flows.

[#81200736]
* Instant/Deferred controllers can now generically manipulate visitor data.

[#81200736]
* PrisonerDetailsController now creates a new session without any visitors.

[#81200736]
* Fixed failing tests around missing visitor in the visitor array in the session.
* Fixed tests in the deferred flow around a different type of visitor present.

[#81200736]
* There's something funny about how fields are named when using _field methods, used _field_tag instead.

[#81200736]