This adds a recipe for iterative closest point weighted by localization precision to register one point cloud to another. This was built to address slight shifts and rotations in a cell's position before and after washes in some PAINT experiments.

While this works for my current purposes, we may want to add a parameter for known offsets between two targets and add this as part of the weighting.

My convergence criteria is also pretty poor, but absolute_orientation() naturally converges so it's OK for now.

Also, I did not implement scaling. Could consider adding it.

• Better convergence conditions
• Fix weighting in rotation matrix to sum to 1