Improve form-field "file" (and subclasses) - add clear button for clearning files/images added added in a prevision revision (unless flag "sticky" is used) - tie revisions of the FormPage/WorkflowInstance with the revision of the uploaded file (the content of the formfield is now a list of attribute value pairs that might contain a revision_id) - allow multiple uploads of files with the same name (distinguish with reusing old content) - caveat: export should strip the revision_id from the content of the form-field.