Plone 5 compatibilty

[tomgross]

Make compatible with Plone 5
Port tests to plone.app.testing
Use custom testing portlet to be independent from Plone changes for testing
added buildouts for Plone 4.3 and Plone 5

[keul]

@tomgross great!

I'm not only convinced about 2 changes here:

• setup.py version is 1.2.3.dev0. This will trigger the zest.releaser syndrome where every new release seems a bugfix release just because releaser will click "enter". You added lot of new features and dropped Plone 3 compatibility. I think 1.3.0.dev0 will be better.
• metadata.xml to 1003: same as above. 1100 is IMO better. Using 1003 wil make impossibile for anybody to release a new Plone 1.2.x version

[tomgross]

Thanks for your feedback @keul !
I updated master with your suggestions