Merge branch 'master' into assembled

This is a no-op merge, explicitly considering and rejecting the
submodules from the master branch.  After this merge, future merges
from the master branch will pick up any content changes.

  $ git merge --log --no-ff --strategy ours master

* master:
  setup: Add a submodule with student-setup utilities
  version-control: Add a submodule with my subject-level notes