Stop using legacy translated columns in queries

The work is required to support the feature that will allow non-
English editions (https://www.pivotaltracker.com/story/show/45582477).

That story relies on a newer version of globalize3, which treats
legacy translation columns differently, the upshot of which is that we
need to drop these legacy columns before we can use the never version.
This commit updates the existing code to no longer user any legacy
columns. There will be a subsequent commit to drop the legacy columns
once this commit has been successfully deployed.

This removes the default scope on Organisation as there is no
sensible way to have a default scope that ordered by the associated
translation name. Besides, default scopes are bad for you...
Organisations are now explicitly ordered where appropriate.
Editions get a sorted_organisations scope

We use sorted_editions to list organisations related to an edition in
alphabetical order. This is here primarily so that
WorldLocationNewsArticlePresenter can share the same interface as a
other editions with organisations, making it easier to use them
interchangeably in front-end views.