PEP 420 native namespace

[petschki]

Part of plone/Products.CMFPlone#3928

[mister-roboto]

@petschki thanks for creating this Pull Request and helping to improve Plone!

TL;DR: Finish pushing changes, pass all other checks, then paste a comment:

@jenkins-plone-org please run jobs

To ensure that these changes do not break other parts of Plone, the Plone test suite matrix needs to pass, but it takes 30-60 min. Other CI checks are usually much faster and the Plone Jenkins resources are limited, so when done pushing changes and all other checks pass either start all Jenkins PR jobs yourself, or simply add the comment above in this PR to start all the jobs automatically.

Happy hacking!

[petschki]

@mauritsvanrees whats the desired maintenance branch here: 5.0.x or 5.x if we release this as 6.0.0 with PEP 420 for plone 6.2 ?

[mauritsvanrees]

@mauritsvanrees whats the desired maintenance branch here: 5.0.x or 5.x if we release this as 6.0.0 with PEP 420 for plone 6.2 ?

That would be 5.x. I have created the branch and updated the sources of 6.0 and 6.1.

[mauritsvanrees]

LGTM.

I have added some commits to move to a src-layout, and have removed the six dependency and an import other unittest2.