Canvas Layers

A system agnostic module to add and show/hide drawings and tiles on the canvas based on layers. The GM can simply select layers and create things on the canvas as usual. GM and players can then individually toggle the layers on and off as they please to avoid clutter and focus on certain information.

The initial usecase I've desired is a worldmap with layered information. You can see a partial example including Regions, Cities and Places Of Interests as layers in the readme of the project github.

I've got a few last things to fiddle with, but otherwise I'll be good to release a version of it once v13 stable drops (or possibly earlier if I'm fidgety).