Some optimizations in view of as-built conditions:
- Bugfix: For sTGC's we measure strips in pitches, (3.2mm), not width (2.7mm).
- Optimized the sTGC as-built transformation to handle positions between strips, as it is for MM (not to put everything on the strip center).
- Some protection for layers or cathode board elements that may not have as-built corrections at all.
- Finally, I noticed that the B-field correction can kick a cluster position slightly out of the active area (only for clusters on the very outmost strips). It's not the job of the as-built transformation to reject those cases, just to correctly apply the transformation. Applied the necessary change for this.