This release is dedicated to knirch, mcandre, Dridi,
ptman, pihentagy, Riviera, and everyone else who keeps
submitting bug reports and feature suggestions!
* Checks now use Writer monad instead of State
* Parser no longer emits notes unrelated to parsing.
* All checks are now passed a parameter value, containing shell type,
map from notes to parents and such. This eliminates recalculation
and removes the need for a special group of parent examining checks.
