Modify compute_per_tile_warp.py and offset_yaml.py to iterate to refine transform, and to preserve the centroid of each tile
Correct Y-range in compute_per_tile_warp.py
Increase Z-tolerance to 75 in estimate_translations.R (probably no effect)
Report Z0 during running of estimate_translations.R
Revert to xyrot3 type matrix in offset_yaml.py
Include cleverer choice of when to pad out points in update_transforms_affine_z.py