Unify logo name methods

Unified the calls to get a name to put in a logo into a single place.

Switched single line instances of organisations to use name rather than
formatted name.

Removed title from topical event link as the title contained the same as
the link text making it unnecessary.

https://www.pivotaltracker.com/story/show/45936735
Fix: Should set related_policy_ids not related_document_ids

This clears the document associations that have been set
Fix: Form helper expecting related_policy_ids not objects
Merge pull request #330 from alphagov/logo-formatted-name

Unify logo name methods

https://www.pivotaltracker.com/story/show/45936735
Fix tests to use related_policy_ids not related_document_ids
update tests: use document.related_policy_ids
Import italian translations

Removed #NAME? values that were obviously results of an Excel mistake.  Also regenerated to have missing keys.
Fix test: related_policy_ids expect policy ids not documents
Missed another document -> policy.id in the test