Data loss occurs when the creator doesn't have a valid ID

CMDBOOK-2425 - Reported by Dark_Arc

This can occur due to the console setting a warp, which results in a null player. I've coded a fix for this, and it can be found in the linked PR, although it needs tested by someone to ensure everything works.

https://github.com/sk89q/CommandBook/pull/109

Review linked pull request #109 and the console warp path described in the issue, focusing on how a null player can reach data-saving behavior. Test the reported invalid-creator case and confirm that no data is lost; the issue names no source file or test to run.

Written by the indexing model from the issue text.