Update bootstrap.py to use zc.buildout from 2.x branch
Update CI configuration

- Test under Plone 5
- Do not allow failures under Plone 4.1
- Use code analysis
Add downloads badge
Simplify MANIFEST.in
Do not return status codes on CI
Skip code analysis if not requested

Code analysis seems to be failing under certain conditions on Python 2.6

See: plone/plone.recipe.codeanalysis#77
Add real control panel tests

There is a bug as the  configlet if being left behind.

refs. #12