Allows to create groups layers which collisions are isolated from each other.
I was able to edit the plugin's runtime.js file to fix saving. Turns out the key and the storedGroups variables were being called before being properly defined.
Thanks for the report, will try to fix it as soon as possible.
Alternatively, you can always fork the repo and create a pull request here: github.com/JeyDotC/construct2-layergroups