Collective-iconifiedcategory

-----------------

- Make sure we correctly bypass `can_view` in `utils._check_van_view` when
element is not confidential in case we do not receive `obj` but
`categorized_elements`.
[gbastien]

-----------------

- Factorized call to _check_can_view from utils and views so we are sure that
the check is only done if obj is confidential. This fix a bug where can_view
check was done for not confidential obj and raised an error on download even
though it was displayed in the categorized elements table.
[gbastien]

-----------------

- Added missing translation when updating categorized elements using the
update-categorized-elements view.
[gbastien]
- Use icon_expr instead content_icon on the types fti to define the icon.
Actually we want to define no icon as the type icon is displayed using CSS.
[gbastien]
- Added one additional level to the `content_category` generated by
`utils.calculate_category_id` to avoid same `content_category` generated for
different category group.
[gbastien]
- Added parameter `sort=True` to `utils.update_all_categorized_elements` to be
able to disable time consuming sorting.
[gbastien]

-----------------

- Make the `plone.formwidget.namedfile` `download` view can_view aware.
[gbastien]

-----------------

- Correctly hide to_print and confidential widgets on add and display view
if they were deactivated on the group
[mpeeters]
- Add new events to limit updated informations on parent
[mpeeters]
- Add an option to update only category informations on parent
[mpeeters]

-----------------

- Adapted translations so it is more understandable.
[gbastien]
- Do only call `_cookCssResources` in `category_before_remove` if not currently
removing the `Plone Site`.
[gbastien]
- Make `ICategory.icon` a primary field so we may use a simpler download URL
that is only the `path_to_object/download` without the file name anymore.
This is done to surround a bug in Apache that occurs when the filename
contains the `%` character.
[gbastien]