Completely hide 100 step ccd motor offset

In order to tell whether the controller has been power-cycled, the CCD focus motor steps are offset by 100. That is currently carried all the way out, which is confusing.

The internal positions should be kept offset by 100, but that offset should be taken out everywhere above that.

The positions which non-engineers might use are the arm vertex positions, which are in correctly adjusted microns from one end.