re-engineered _listTypesForInterface to work both with AT and dexterity. Simplified UploadFileTypeVocabulary,
since it now relies on _listTypesForInterface to make the distinction.
Lastly, some flake8 for good measure
Merge pull request #28 from pysailor/master

More dexterity-related fixes
Merge remote-tracking branch 'upstream/master' into upload-viewlet
nicer place for the viewlet
updated history