- deactivate util_createDom and friends due to problems in containers,
loosing properties and the unability to re-enable disabled fields
(maybe browser caching)
- formfield "file": simplify value management
- formfield "file": keep always revision_ids as linkage when going
back in revisions (the revisions of the form page do not
neccessarily correspond 1:1 to the revisions of the contained
file object)
- formfield "CompoundField": update property in instances_attributes
after convert_to_internal