Updated the setup instructions to reflect the current GitHub interface,
and small changes to the lesson template files.

The file is not *needed* for anything, because the information is in
the Git history.  It's just easier to access when it's committed to a
file in the repo than it is to ask curious folks to clone the repo and
run ‘git shortlog’, etc.

This file was removed in 2e05819f (Naming layouts and inclusions more
clearly, 2016-04-19).