[Users] McLachlan cleanup

I want to clean up the McLachlan Kranc scripts. In particular, I want to use consistent indentation, rewrite/augment some comments, change the order in which certain equations and variables are listed, remove unused code, etc. I think now is a good time for this. I don't plan to introduce any functional changes.

I expect these changes to be all over the place. They will likely lead to conflicts if someone else is making changes at the same time. If you are working on changes, please tell me, so that we can avoid such conflicts.

-erik