Make a note to implement memoization using the same tricks.
Add vanilla .cabal file and MPL-2.0 license.

Still need to edit these. The license came from

  wget -4 http://www.mozilla.org/MPL/2.0/index.txt -OLICENSE

which is the markdown used to generate the formatted version at

  http://www.mozilla.org/MPL/2.0/
Support 'cabal install' and add 'cabal sandbox' related 'make' targets.

Ran into an obscure Cabal but along the way:

https://github.com/haskell/cabal/issues/890?source=cc