Zope-traversing

===================

- Remove testing dependency on ``zope.app.publication``.

===================

- Remove stray test claiming a no longer existing dependency on
``zope.app.applicationcontrol``.

- Refactor functional tests to loose dependency on both
``zope.app.appsetup`` and ``zope.app.testing``.

- Simplify tests for the ``browser`` sub-package by using ``PlacelessSetup``
from ``zope.component.testing`` instead of ``zope.app.testing``.

- Simplify ``test_dependencies`` module by using ``zope.configuration``
instead of ``zope.app.testing.functional``.

- Remove testing dependency on ``zope.app.publisher``.

- Replace testing dependency on ``zope.app.security`` with
``zope.securitypolicy``.

- Remove testing dependency on ``zope.app.zcmlfiles`` in favor of more
explicit dependencies.

- Remove testing dependency on ``zope.app.component``.

- Replace a test dependency on ``zope.app.zptpage`` with a dependency on
``zope.pagetemplate``.

==================

- Move ``IBeforeTraverseEvent`` here from ``zope.app.publication``,
as we already deal with publication traversal.

==================

- In ``zope.traversing.api.getParent()``, try to delegate to
``zope.location.interfaces.ILocationInfo.getParent()``, analogous to
``getParents()``. Keep returning the traversal parent as a fallback.

- Bring ``ITraverser`` back from ``zope.location`` where it had been moved
to invert the package interdependency, but where it is now no longer used.

==================

- Make virtual hosting tests compatible with ``zope.publisher`` 3.9.
Redirecting to a different host requires an explicit ``trusted``
redirect now.

==================

- ``AbsoluteURL`` now implements the fact that ``__call__`` returns the same
as ``__str__`` in a manner that it applies for subclasses, too, so they only
have to override ``__str__`` and not both.