moving and updating devolved administration warnings on a policy
Use X-Slimmer-Search-Path header instead of setting the prefix.

The prefix functionality will soon be removed from slimmer.
Unify change notes dropdown and styling

There were many different variants of the document change notes. These
have now been styled universially the same.

Changed the markup produced by change_notes.html.erb to be more
semantic.

Removed the old change notes styles from the different places and
applied new generic styling across the board.

Refactored policyUpdateNotes jQuery extension to work with more semantic
markup. Updated the respective test to work with the new structure.
Merge branch 'master' of github.com:alphagov/whitehall
fixing failed tests
Brad fixed cucumerb tests
making them lists and moving uk and world tags on policy to the head next to topic list
Fix a bug in the conflict partial template.

We were checking whether an edition could be associated with related
policies but displaying topics, and checking whether an edition could
be associated with topics but displaying related policies.

This caused an exception to be raised when the conflict resolution
template was displayed for a specialist guide, as a guide can be
associated with topics, but *not* with related policies.

There were existing tests, checking for a specific heading within the
conflict resolution container, that I was able to extend to check
for the actual related policies and topics.  These gave me failing tests
that I could use to determine that the bug was fixed.

For reference only, the problem was introduced in a combination of
97437877d47475e357680c1c4c3251c050134709 and
73978dd9c4f9eb207e3dc97d58f9ebac264d7cf4.
Merge branch 'master' of github.com:alphagov/whitehall
fixing falied tests
updating nation link in policy head to include and rel external so they adopt the external link icon
Set Google Analytics custom variable `Proposition`.

To be consistent with the mainstream apps, we should be setting this
custom variable to a value dependent on whether the page is showing
specialist guidance related content or inside government content.

Calling Slimmer::Headers#set_slimmer_headers adds headers to the
response which is then interpreted by the Slimmer middleware and the
custom variable assignment javascript is written into the relevant
script tag in the final response.

It would be better to test this in an integration test that actually
uses Slimmer for real, but this is better than nothing.
Rename the 'related' partial to 'related_policies'.

I think the generic name and implementation is a hangover from when
you could associate multiple types of documents with each other.  As all
related documents are now policies we can make that clearer in the
naming of the partial and the implementation.
Rename controller test for consistency.
Enable some tests around specialist guides controller.

Specialist guides can have images so we should test that the
functionality works.

Specialist guides cannot have related policies so I've removed the
commended out test.
Add tests for showing audit trail to all document types.

We already had this test 'macro' ensuring that we displayed the audit
trail on admin publications.  I've extended it so that we can test the
audit trail on other document types.
Test the conflict resolution form on specialist guides

By moving the test out of the policies controller test and into the
should_allow_association_with_topics test macro, we automatically add
the test to the specialist guides controller test, too.
New styling of navigation on guidance pages.
Make change notes box twice as wide.

Some people might write long change notes. For these people we will need
a bigger box. Once we have more data about how people use change notes
this can be adjusted in future.
Revert page navigation for one page guidance pages

Guidance pages which are elected to all be on one page should not use
the tabbed navigation interface. Guidance which is split should still
use the new tabs though.