Fixes necessary for log_events service.
Subclasses can override the name of the attribute to use in calculating
the last-modified time; modified_at is no longer required for
sublcassing Resource.
Migration for rename of log_events.whodunnit column to modified_by_id
Fix javascript errors on page load
Fix related widget service and template
Merge pull request #18 from reciprocity/feature/related-objects

Make related widget work
Merge pull request #15 from reciprocity/feature/js_events_log

Changes needed to fix the log_events service.
people selector
removed slugs from lists
Merge pull request #19 from reciprocity/feature/people_selector_design

people selector
Added GGRC.make_model_instance and GGRC.infer_object_type to allow the packaging of GGRC.page_object into a proper model instance