Zope.app.publication

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- Moved the publicationtraverse module to zope.traversing, removing the
zope.app.publisher -> zope.app.publication dependency (which was a
cycle).

- Moved IHTTPException to zope.publisher, removing the dependency
on zope.app.http.

- Moved the DefaultViewName API from zope.app.publisher.browser to
zope.publisher.defaultview, making it accessible to other packages
that need it.

- Look up the application controller through a utility registration
rather than a direct reference.

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- Use ``zope:adapter`` ZCML directive instead of ``zope:view``.
This avoid dependency on ``zope.app.component``.

- Update imports from ``zope.app.security`` to ``zope.authentication`` and
``zope.principalregistry``.

- Use ``zope.browser.interfaces.ISystemError`` to avoid dependency on
``zope.app.exception``.

- Refactored tests so they can run successfully with ZODB 3.8 and 3.9.

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- Adapt to the removal of IXMLPresentation from zope.app.publisher which
was removed to adapt to removal of deprecated interfaces from zope.component.

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- Use ISkinnable.providedBy(request) instead of IBrowserRequest as condition
for calling setDefaultSkin. This at the same time removes dependency to
the browser part of zope.publisher.

- Remove deprecated code.

- Use built-in set class instead of the deprecated sets.Set and thus
don't cause deprecation warning in Python 2.6.

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- Import ISite from zope.location.interfaces instead of deprecated place
in zope.app.component.interfaces.

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

- Now ``zope.app.publication.zopepublication.ZopePublication`` annotates the
request with the connection to the main ZODB when ``getApplication`` is
called.

- Removed support for non-existent Zope versions.