make note_index.item a schematized object relying on an enum
Add note_index_item_type enumeration I18n translations and also replace spaces in enumeration values with '_'
handle validation errors that don't have invalid_object method
update importer to make note_index_item
unpend the ferris integration test
Merge pull request #523 from hudmol/enum-for-note-index-item-type

make note_index.item a schematized object relying on an enum