Weight obj fucc by inverse var of diff dist.

Couplings with tighter difference images become more useful. Made
possible by the better masking we now have.

Previously the weight was unitary.
Delete offset images post mosaicing to save space.

This can be toggled if for debigging.
Create LockedBlockFactory

This pipeline combines frame stacking and block production into a single
step for cases where we can reasonably assume that all frames in the
image see a uniform sky. This reduces the 'flexibilty' of the block.
(Made for Elixir-LSB images).

Here we demonstrate mosaicing, still need to build in noise mapping.
Use diff pixel sigma clipping with ChipStacker
ChipStacker now iterates to solve frame offsets

We iterate until there is fractional offset convergence or there is a
max (usually 10) number of iteration.
LockedBlockFactory creates noise maps