Products-genericsetup

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

Breaking changes:

- Drop support for Python 2.6.

- Require Zope 4.0a3 as minimum supported Zope version.

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

- Allow registering the same profile twice if it really is the same.
This is mostly for tests where the registry may not be cleaned up
correctly in case of problems in test teardown.
If you register the same profile twice in zcml, you still get a
conflict from ``zope.configuration`` during Zope startup.
[maurits]

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

- Added a ``purge_old`` option to the tarball import form.
By default this option is checked, which matches the previous behavior.
If you uncheck it, this avoids purging old settings for any import step
that is run. [maurits]

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

- Stopped using a form library to render the components form.

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

- Made ``_profile_upgrade_versions`` a PersistentMapping. When
``(un)setLastVersionForProfile`` is called, we migrate the original
Python dictionary. This makes some code easier and plays nicer with
transactions, which may especially help during tests. [maurits]

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

- Allowed overriding required and forbidden tools in ``toolset.xml``.
If a tool is currently required and you import a ``toolset.xml``
where it is forbidden, we remove the tool from the required list and
add it to the forbidden list. And the other way around. The
previous behavior was to raise an exception, which left no way in
xml to remove a tool. Fail with a ValueError when the ``remove``
keyword is used. The expected behavior is unclear. [maurits]