Make all damage variables the same sign#63

Draft

corakingdon wants to merge 4 commits intomasterfrom switch-signs

+43-50

Commits on Feb 25, 2020

switch signs of impact variables to be damages
Kingdon
committed
fix validation tests for these variables
Kingdon
committed
start updating docs
Kingdon
committed

Commits on Feb 26, 2020

remove duplicate test
corakingdon
committed