Added "clone edition" mechanism.
Data migration for dates. TODO: use migrated data.
Fixed bugs in field names.
Implemented edition-aware "item by year" display.
Added editions to release date display when appropriate.
Moved date editing to edition level.
Eliminated obsolete code/DB table.
Data migration for credits. TODO: display migrated data.
Progress on item credit display.
Fixed person credit display.
Added credits to edition editor.
Restored credit controls in item editor.
Removed obsolete table/methods.
Added full text tables.
Copy credits when cloning an edition.
Safe delete mechanism.
Copy credits when attaching existing item.
Special message for empty note list.
Added ability to create full text sources.
Switch search from POST to GET.