Use correct extension for versions partial

* Rename .erb to .html.erb
Remove faulty javascript call

* We haven’t had versions JS for a while now
Cleanup version and changeset display

* Generate a human readable title based on the type of changes
* Use ordered lists, definition lists and bootstrap wells rather than
nested tables
* Use friendlier dates

Caveats are that the logic for displaying the changes is a little ack n
slash and could do with some love. Most of this comes as result of our
models no longer matching displayed labels.
Move versions logic into helper

* Create methods for friendly title, summary and field names
Update styles for bootstrap 3
Include created message in version history
Make mapping type switches more friendly
friendly_changeset_title only needs the changset

* Refactor out the version
Introduce version helper tests

* Test new friendly version helper methods
* Tweak cucumber features to include some of the friendlier messages
Make http status version message change resilient

* Instead of using the old value, use the new value
* Provide an alternative if the new value isn’t a recognised one
Rename changeset_values to changeset_old_to_new

* Use a more descriptive method name
Rename changeset_field to field_name
Micro-optimise strings

* Switch to single quote strings
* Use ‘case field’ rather than if statements
Merge pull request #157 from alphagov/a-better-history

Improve mapping history with friendly messages