Devlog #29: New feature: Multi-layer!

You can now build circuits across two layers!
I added vias, so you can connect the two layers together (obviously).

When you place a via, it’s added on both layers, it basically works like a wire.

I also finished the 7-segment decoder: 3bit input, supporting only 0-4 for now. The other values are just don’t-cares.

Next steps: polish the code and UI, then add some documentation.