a few more additions to the knotwork generator

• i added some control options so now there's a little more interactivity aside from hitting the randomize button over and over
• saved svg files now store the seed and parameters used to generate the shape in a comment
• added a few more transformation options for the background, including stripes and a spiraling non-affine transform

sadly, this will probably break any seeds you've already seen. hopefully the param stuff will make that less likely if i update again in the future.

that's about it