Jim McStanton

@danigb I took a crack at this. The root note determination in there wont catch all chords, but I think it is order independent now. There is a fallback path...

Hm, just noticed that master is building just fine without this change: [master build](https://circleci.com/gh/jaspervdj/hakyll/123). Has this error been seen before?

FWIW, I also tried building master with cabal using the same process that master build used ```sh $ cabal sandbox init $ cabal install --only-dependencies --enable-tests --jobs=1 --flags="+buildWebsite $ cabal...

Latest change resolves this issue for myself and against Circle CI