I have just finished
DM-1920, which brings over the HSC changes, which were very extensive. However, it needs to build against a new version of the GalSim package, which is only available at present on lsst-dev, as version 1.2.lsst1. I'll keep working on getting a version of that out that can be installed via eups distrib, but it's now possible to work on lsst-dev in the meantime.
This issue absolutely needs to be rebased on top of master before doing any more work, because
DM-1920 changes essentially everything underneath it. It may actually be easier to start over again, but it's probably worth seeing how bad the rebase is first.