first shot at new subtraction operator, makes tests fail. Are tests wrong?
first shot at new subtraction operator, makes tests fail. Are tests wrong?

gidden/cyclus,gidden/cyclus,hodger/cyclus,gidden/cyclus,hodger/cyclus,Baaaaam/cyclus,Baaaaam/cyclus,hodger/cyclus,hodger/cyclus,rwcarlsen/cyclus,mbmcgarry/cyclus,hodger/cyclus,rwcarlsen/cyclus,mbmcgarry/cyclus,mbmcgarry/cyclus,Baaaaam/cyclus,rwcarlsen/cyclus,mbmcgarry/cyclus,gidden/cyclus,rwcarlsen/cyclus