[WIP] WLS_sparse2 solver#121

Draft

bdestombe wants to merge 9 commits intodtscalibration:mainfrom

bdestombe:master

Commits on Jun 4, 2020

Commits on Jun 5, 2020

New solver that supports a priori information, which allows for sequential calibration in chunks.
bdestombe
committed

Commits on Jun 6, 2020

Commits on Jun 7, 2020

Commits on Jun 8, 2020

Implementing `WLS_sparse2` as alternative solver
bdestombe
committed

Commits on Jun 10, 2020

Added comma in documentation of ufuncs
bdestombe
committed