Snapping in GUI Editor

Issue description

Could you add a switch that would toggle snapping for components in the GUI editor? This would make making a GUI look good much easier.

Also if possible could you add a way to change the background of the GUI image. I know you can upload an image that looks just like the GUI but in a different color but it's so much work for such a small thing.

Issue comments

We will improve the GUI editor in future releases. I will keep this ticket open for the progress monitoring.

Can you also add a faster way to add slots? If you want to make a new container block like a chest, you need to add the slots one by one and it's boring and they look weird... Adding a way to make easily a grid of slots would make everything easier