Updating the Author value on drawings throws errors

[sneat]

Attached is the error being thrown when MLT tries to update the author value of the drawings on a scene:

This happens because d._id is undefined. It should either be d.id or d.data._id.

Steps to replicate:

1. Create a scene with MLT drawings in it.
2. Export the scene to a module compendium.
3. Create a new world (so that the GM userID changes).
4. Import the scene from the module compendium. When it first loads, it will throw these errors.