previousSnapshot incorrect for nested tables.

[SyferTheProto]

Currently Charm uses table.clone inside of the server to store the previousState, this is an improper implementation of this.
table.clone should be replace with a deep copy instead since table.clone returns a shallow copy of the table meaning if a table inside it updates, it will update in the copy too.

[DanyloBoy]

I can confirm this is an issue, I have already had to make my own work around for this issue just so I can use tables in tables