Sculpt smear & paint stroke: add new stamps when the relative position between imp and sculpt/painting changes

Currently smears and strokes only stamp a new position when the shape/fleck's transform changes enough. This makes it difficult to use animation/logic to help us build more complex and precise shapes, using the grid to keep our imp still as the logic moves the object around as we "draw" the shape like a CNC machine.

John Beech has had to use stamps instead of a controlled smear, which takes more time and hassle to use. https://twitter.com/Johnee_B/status/1430922252506341383?s=20 With this change he could use smear, on-grid, and do the whole shape in one go easily.

I have shown techniques using these methods to use paint to draw precise shapes, but I cannot use the grid to keep the imp still--which is the ideal situation. The frustrating part of using this stuff is having to wobble the imp a little or constantly rotate the shape (which means you can only use certain shapes) so that Dreams realises you still want to stamp new positions for the smear/stroke. https://youtu.be/J8auW7S-Xfc

I've also made a QR code "printer" in Dreams (unreleased), where you need to hold a smear. But there's a lot of nonsense I need to do to remind Dreams I'm still smearing a shape. The result is either squares as expected but messy and wobbling all over the place because of imp drift and such... or using cylinders so I can rotate constantly, which is frustrating as it's not the expected look for a QR code for the most part. And in either case, because I need to move it enough for Dreams to make a new shape, it has to be slower than it could be to make sure it "prints" properly.

I think this change shouldn't cause any problems for existing techniques, and would simply allow this technique to work a lot better, more efficiently, and more "as expected" with the tools we have.