[cctbxbb] New top-level module: fast_linalg

Hi, this is an advanced warning for the introduction of a new top-level module named fast_linalg. In a couple of days, I will push it in one go as 25 commits but don’t be scared, nothing is changed outside the top directory fast_linalg, which also means it is not configured by default. Thus there cannot be any disruption but I thought it would be polite to warn all cctbx developers. The module features the automatic installation and integration of OpenBLAS which I have used to speed up smtbx refinement. I will commit that work later. Best wishes, Luc J. Bourhis