Cabal init.
Forgot Setup.hs.
Push some source.
Update cabal file.
Things at least compile now.
Multiple changes.

Bad git style- some documentation added, a couple of new functions,
and linting.
Make Appenders/Prependers data decls.

This means I don't need to export Digit/Tigid anymore, and the
API is cleaner.  Also, more documentation.
Documentation is complete.