Sliding dropout dimensions

For each dropout, we have a set of dimensions to locate the ends of the stays with respect to the rear axle. We call these dimensions Cx, Cy, Sx, and Sy. Different styles of dropouts will have very different values for these dimensions. When using a sliding dropout, we want to measure these dimensions from a stable reference point, not one that's sliding back and forth like the rear axle. Therefore, as a rule, we use a point along the sliding track or in the case of a rocker dropout, we use the pivot point. However, once we go to mount the dropout in a fixture in order to tack the frame together, we'll want dimensions such as Cx, Cy, Sx and Sy that actually go to the axle (or dummy axle in the case of a framebuilding fixture). Therefore, in BikeCAD version 23, we have new dimensions Cx for sliding dropouts, Cy for sliding dropouts, Sx for sliding dropouts and Sy for sliding dropouts that do just this. Note that as the rocker dropout is adjusted the default dimensions continue to hold their original values while the Cx, Cy, Sx and Sy for sliding dropouts, adjust to reflect the current position.