Running "cabal check" no longer complains of anything. Running "cabal haddock" reports 100% coverage.
- Converted the various index to square and algebraic squares to use Maybe types and handle errors sensibly. - Added tests for a few missing items and cleaned up some of the existing tests a bit. - Ran HPC reports on the whole thing and, aside from a few unused Show instances and one thunk in some (intentionally) bad data, everything is executed by the test suite.