Boost based on the currently selected locale.
Merge branch 'master' into search-translated-articles
Fix bug 972533: Enhancements to admin handling of deleted pages.

This adds a new manager to Document, which does not perform any
filtering based on deleted status, and uses that manager for the
admin; this ensures the admin always shows all Documents currently in
the database.

Building on that, the admin filters now include one to show only
deleted Documents.

The admin actions for Document are also updated:

* A new "purge" action is added, to bulk-purge deleted Documents.

* A new "undelete" action is added, to bulk-undelete deleted
  Documents.

* The built-in Django "delete" action is removed, since we want people
  using the standard deletion UI (and because the admin delete action
  bypasses the model delete() method, which is not what we want for
  deleting Documents).
refer to English via a setting
Merge branch 'master' into search-translated-articles
Add search section to 'Site Operations' section.
Store information about the parent document for translated docs.

- Show the parent in the search results.
- Introduce a SiteURLField to simplify rendering it.
- Reindex all translations of a document whenever a doc is rendered.
Use 4 threads to run the celery tasks.
Merge branch 'master' into search-translated-articles
Fix the filtering to do the follwing:

- when in English only show English documents
- when in non-English mode show both language documents as well as English
Reverted some previously removed parts of the result template to better work with the new search method.
Render document URLs with the already defined Document.get_absolute_url method instead of inline.
fix bug #1002371 - don't lose the query parameters when switching languages.
Restored some missing code and clarified some other.
Commented in logging setting for elasticsearch again.
Revert log level.
Fix bug 1008828: Show correct locale/slug in page move error.

The root of the problem was a child page move failing after the
child's locale/slug had already been changed in-memory; in that case
the new locale/slug would end up in the error message instead of the
original.

Now the original locale/slug get stashed away prior to attempting the
child move, and if the child move fails they get inserted in the error
message to ensure the error points to the correct URL.
Make the branch work in prod without breaking.
Make selection of links into Quick Links less greedy for toggleable lists.
Fixed anchor is null issue pointed out by @darkwing