symmetry test passes
even better symmetry test, forces out better behaviour in rejection case
Make match function a bit more realistic, make the matching cycle a fold, make a test pass
refactor away an undefined - a match between two orders has only three possible outcomes
split out an Order module
refactor - reduce appearance of 'Side'
make the types simpler, remove some dead code
whitespace
more tidying
free a signature of concrete
remove a binary file
rename a function in order, stop exposing it
remove an unused where clause