initial implementation of changeCountOptimization, still ugly
initial implementation of changeCountOptimization, still ugly

mobxjs/mobx,romseguy/mobservable,sandals/mobservable,sandals/mobservable,andykog/mobx,dschalk/mobservable,ryanbraganza/MOBservable,ryanbraganza/MOBservable,andykog/mobx,romseguy/mobservable,mobxjs/mobx,mweststrate/MOBservable,mweststrate/MOBservable,sandals/mobservable,mweststrate/MOBservable,mobxjs/mobx,dschalk/mobservable,mobxjs/mobx,ryanbraganza/MOBservable,andykog/mobservable,romseguy/mobservable,dschalk/mobservable,andykog/mobservable