Maybe Bug / Feature Request: key change sync

[ozum]

When key of an object is changed, all references to old key become broken. Maybe same is true when file name is changed, but I didn't try.

May I suggest:

1. Provide an option to update all references to old key name in all files when key or file name is updated.
2. Also please add a tool to list broken references and a way to update them. (I know this is possible in raw code, but a tool would be helpful)