Fix 'plone.belowcontentbody.relateditems' viewlet

Avoid trying to display items if the user has no permission to view them (like content in Private state)
Update package dependencies

Clearly specify this branch is for Plone >=4.3 only (in fact, should be 5.0).
Remove dependency on unittest2

We are not going to test against Python 2.6 anymore on Plone 5.0; use test discovery also.
Fix body class attribute errors when the user role contains space
Merge pull request #30 from jianaijun/master

Fix body class attribute errors when the user role contains space
Ported tests to plone.app.testing
Merge pull request #31 from plone/tomgross-ploneapptesting

Ported tests to plone.app.testing
open plone.org in a new page/frame
Merge pull request #32 from muellert/master

open plone.org in a new page/frame
Merge remote-tracking branch 'origin/master' into barceloneta