Smoothie's G-code processor apparently doesn't know the difference between lines beginning with Gxx and TOKENS beginning with Gxx.
This means that when we do M665 A, B, C, D, E, F, G, H, I, L, R, it sees G as a new command, which I'm pretty sure is a bug!
G, H, and I have been changed to T, U, V.
Added preliminary code to test points near the towers, and the midpoints between those. Also, made most of the geometry option setters reset the kinematics by themselves. I don't think there's a good reason why they shouldn't!