This avoids the `AssertionError: app must call start_response before returning`
error message.

Currently this is not fully functional. repoze.retry causes errors
for failing to call start_response. Exceptions like NotFound aren't
turned into their HTML form by neither WebError nor paste#httpexceptions.

This is a very limited copy of Pyramid's pserve script.

Provide both a ZServer based etc/zope.conf and 'no HTTP server'
etc/wsgi.conf, both based on a common etc/base.conf.

Also move the full configuration options into an etc/example.conf

These scripts are either installed by a virtualenv or buildout and
conflict when creating an instance home inside the same directory.

Automatically create a pip requirements file based on the prod versions.

Currently there are a small number of test failures and errors.

I was too quick to remove it.

Copy more of the zope.testbrowser.testing code, as it got moved
into zope.app.testing and we want to avoid a dependency on any
zope.app package.

This is no longer a persistent object.

Apply hotfix 20160419 [master]

Needed by Products.five.

It imports ObjectEvent from zope.interface.interfaces which was moved there in 3.8

Optimize "OFS.ObjectManager.__contains__" method