Merge branch 'master' into mockup-issue-220

* master:
  add folders to test for migrating references
Merge branch 'mockup-issue-220' of git://github.com/plone/plone.app.contenttypes into mockup-issue-220

# By Alessandro Pisa
# Via Alessandro Pisa
* 'mockup-issue-220' of git://github.com/plone/plone.app.contenttypes:
  pinning plone.app.testing version
Merge remote-tracking branch 'remotes/origin/mockup-issue-220' into mockup-issue-220

* remotes/origin/mockup-issue-220:
  Modernize robot tests
  make p.a.c. startup without Archetypes (fixes #99)
  Fix robot test setup by pinning the robot related packages to the latest version.
  Use the latest p.a.testing release.
  fix fix calculation of minutes for the estimated time
  plone5 branch renamed to master
  Update setup.py
  use safe_unicode for indexer (fixes #104) and pep8
  Fix #62: Keep ModificationDate during migration.
  add convenience-method to add the browser-layer to the request
  add failing test to confirm that the ModificationDate is changed on migration when content of folders is migrated (also when the folders containing the content is migrated)
  add forgotten xml for the import-step
  auto-enable multilingual-behavior if plone.multilingualbehavior is available