Add support for jumper plates

It would be great to support studs placed off-grid (shifted by .5 stud distance in any direction) to create jumper plates, e.g.:

- https://www.bricklink.com/v2/catalog/catalogitem.page?P=3794b
- https://www.bricklink.com/v2/catalog/catalogitem.page?P=1745
- https://www.bricklink.com/v2/catalog/catalogitem.page?P=87580
- https://www.bricklink.com/v2/catalog/catalogitem.page?P=65509