FIXED remix of helix slide by andy40 + 4 varients

This is a fixed version of the spiral by andy40, which was a tiny bit too short, so I've made it a height more compatible with current gravitrax spacer measurements. I have, in adition, added a very tight connection ring to keep the helix from wobbling, a 360 degree version (mistakenly called 180), a 60 degree version (mistakenly called 30degree in the file), a 120 degree version, and a super tall 180 degree version (that one is my favorite). These are basically patched together from a sliced up 3d model of andy40s original, but I've tried to ensure that they are all standard spacer heights. I had to make the walls taller on some of these to compensate for greater speeds, but they have all been printed and tested and proven to get the job done. Hope you all enjoy these remixes.