Please port fastfinder

[RoyWilliams]

Hi Ken and Michael
I have made template code so that you can port the business logic from fastfinder to LSST as a FeatureGroup. This means that the "Incline" values will be available to all Lasair users, and the fastfinder annotation will no longer compute numbers, rather just make a judgement on those numbers.

There is a new branch for this, and it tells you how to run the code on a sample alert. The code is here. Can you meet up and try to port Michaels code into this?
Roy