Merge branch 'master' of https://github.com/ichim-david/zopyx.plone.migration

Conflicts:
	docs/HISTORY.txt
	setup.py
- fixed edge case where obj.objectValues recursed infinitely (SimpleAlias)
- add more verbosity to exporter.py
generalize ReferenceField behaviour (eg. relatedItems) to use 'getRaw' method to avoid pickling errors
add Topic support (see HISTORY)
merge upstream/master
fix missing Newsletter 'id' schemadata
fix topic criterion export
various importer fixes for exporter enhancements (see HISTORY.txt)
disable subtopics. fix syntax
Deal with Plone 2.1 GRUF groups