Pin zope.app.wsgi to <4.0dev in tox.ini too

See commit 3561efd35bf3b5a9a2b5666a7711337f32c09f01
PEP-8-ify setup.py, add PyPI classifiers
Remove Python 3 from .travis.yml, use tox to run tests

Python 3 support was added in the py3 branch which remains unmerged.
Oops, don't run the same tests twice
Merge pull request #1 from minddistrict/master

Improve the publication factory lookup by falling back to a more generic
registration if the specific factory chooses not to handle the request
after all.

Also, fail clearly by raising an configuration error always if no
handling factory can be (instead of returning None in that case, which
is not handled properly in the callee).
Ignore .tox
Include tox.ini in the manifest