Fix tests for Plone 5

This makes the tests pass against Plone 5.
Two problems were fixed:

1. `browser.open(obj_path + '/edit')` did not work because `plone.protect` did protect it. There are a lot of places where things like that were done, therefore I've disabled `plone.protect` on the testing layer as quick fix.
2. The folder contents view is different, which broke a copy / paste test. I've changed it so that it does not use folder contents but the copy / paste actions instead.

Related to plone/Products.CMFPlone/issues/223

/cc @tisto
Seems like adding p.a.versioningbehavior into the PloneTestCase alltests group leads to test failures in plone.outputfilters (just tried it locally). Not sure which of the packages is responsible. Though, since we want to move those packages to plone.app.testing I guess it is not worth the effort to investigate that problem.