Plone.app.linkintegrity

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

New:

- Introduce IRetriever adapter for customization flexibility.
[tomgross]

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

- Remove xml:lang and wrong xmlns from delete_confirmation_info.pt.
[vincentfrentin]

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

- Don't show delete_confirmation_info twice in delete_confirmation. Fixes 27
[pbauer]

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

- Drop the Archetypes-dependency by switching to use zc.relation instead of
reference_catalog (Products.Archetypes).
[bloodbare, pbauer, vangheem]

- No longer intercept the request on manage_deleteObjects. Instead only
inject a warning in delete_confirmation. This means that deleting with
other methods (like manage_deleteObjects, plone.api.content.delete, ttw
in the ZMI) no longer warns about linkintegrity-breaches.
[bloodbare, pbauer, vangheem]

- LinkIntegrityNotificationException is not longer thrown anywhere.
[bloodbare, pbauer, vangheem]

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

- Fix html structure in confirmation.pt
[vincentfretin]

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

- When using the update view for dexterity objects, only call the method if
object provides IReferenceable
[frapell]

- Removed Zope 2.10 compatibility from publisher monkey patch.
[davisagli]