Permission checks when displaying bibliographical tables.

Added permission checks to make sure that the buttons that allow
editing are shown only when the user has the right permissions.
Dropped an old unused view.
Added a development watermark to the background.
Added the `settings` variable to context_processors.

This variable will contain *selected* values from the global Django settings.
Updated the decoration of bibliographical references.

The old abbrev and info views were dropped in favor of a more RESTful
method to get items and primary sources. The decoration code now uses
the new methods.
Fixed a submission bug.