lsst::coadd::chisquared; Support for chi-squared coadds

Introduction

Code to support chi-squared coaddition of images: sum of image^2/variance

Functions available from C++ and Python:

• lsst::coadd::chisquared::addToCoadd: add good pixels from an Image or MaskedImage to a chi-squared coadd

Classes available only from Python:

• lsst.coadd.chisquared.Coadd: a chi-squared coadd with a method to add additional exposures