Add alt text for image widget
Fix HTML validation

The previous code was generating:
  <select required="True"><!-- required -->
  <select required="False"><!-- non required -->

This fixes html validation, and generate:
  <select required="required"><!-- required -->
  <select><!-- non required -->
login_required support for UrlconfIncludePages

For anonymous users, we don't install the login_required urls. This
means that when they visit a login_required url, they get a 404 -- not
the expected redirect to the login page. To rectify this, try resolving
the request again, this time only using UrlconfIncludePages. If it
resolves this time, we know to redirect_to_login.
stopPropagation of edit button
Don't ever display edit form if not editable.
rm a funny to_json method

This was used for testing a loooong time ago, it's not needed any more.
Fix the migrations

  - mezzanine dependency for the WidgyPage migration
  - Completely remove a very old model that depended on mezzanine
Fix LinkField circular import

get_all_field_names includes related fields, which means it populates
the appcache. We don't want to populate the appcache while loading
models, or we'll probably have a circular import.
Merge branch 'edit_button_fixes'

* edit_button_fixes:
  Don't ever display edit form if not editable.
  stopPropagation of edit button
fixed edit_url tests
Merge branch 'master' into design
resize select inputs in widget form fields