Fix loading of specific file

abspath is not a standard command. Replace with a case statement.
Merge branch 'develop' into wdtk
Fix for external requests.
Calls to API that are expected to return JSON are always expected to return something, even when there are no errors.
Ensure (at least in the most basic cases) that views support recent "external request" changes (mainly that InfoRequests no longer necessarily have a User).

Conflicts:

    app/controllers/admin_request_controller.rb
    app/views/request/show.rhtml
Fix bug introduced in commit 049198b
Beef up mocks

Add the user_name and is_external? properties to the InfoRequest
mock objects used for view testing, where necessary.
Also handle moved and deleted incoming messages.
Re-adding the serving of cached attachments direct from Apache.
Merge branch 'release/0.6.3' into wdtk

Conflicts:
    app/controllers/admin_request_controller.rb
    app/views/request/show.rhtml
    spec/models/info_request_spec.rb
Merge branch 'release/0.6.3' into wdtk
Merge remote-tracking branch 'origin/release/0.6.4' into wdtk

Conflicts:
  app/views/request/show.rhtml
  spec/models/info_request_spec.rb
Restore survey variables.
Merge branch 'release/0.6.5' into wdtk
Merge branch 'wdtk' of git.mysociety.org:/data/git/public/alaveteli into wdtk
Merge branch 'master' into wdtk
Add a since_date parameter to the API feed
Merge branch 'develop' into wdtk
Add some indexes based on queries appearing in the SQL slow queries log.
Fix Atom version of api_body_request_events

Remove duplicate <created> element, and add an <updated> element
to each entry.