feat(library/data/category.lean) the definition of category doesn't depend on 'mor' anymore; make iso a class; add theorems
feat(library/data/category.lean) the definition of category doesn't depend on 'mor' anymore; make iso a class; add theorems

johoelzl/lean,javra/lean,htzh/lean,Kha/lean,rlewis1988/lean,soonhokong/lean-osx,fgdorais/lean,eigengrau/lean,rlewis1988/lean,soonhokong/lean,johoelzl/lean,fgdorais/lean,johoelzl/lean,javra/lean,levnach/lean,levnach/lean,avigad/lean,soonhokong/lean-osx,dselsam/lean,levnach/lean,Kha/lean,javra/lean,rlewis1988/lean,soonhokong/lean-osx,soonhokong/lean-windows,fpvandoorn/lean,soonhokong/lean-osx,sp3ctum/lean,fpvandoorn/lean2,fpvandoorn/lean2,c-cube/lean,digama0/lean,leanprover/lean,johoelzl/lean,leanprover-community/lean,leodemoura/lean,UlrikBuchholtz/lean,UlrikBuchholtz/lean,soonhokong/lean-windows,soonhokong/lean-windows,Kha/lean,dselsam/lean,fpvandoorn/lean,c-cube/lean,fpvandoorn/lean,leodemoura/lean,digama0/lean,leanprover-community/lean,leodemoura/lean,leodemoura/lean,fpvandoorn/lean2,fgdorais/lean,dselsam/lean,eigengrau/lean,UlrikBuchholtz/lean,avigad/lean,avigad/lean,leanprover-community/lean,fgdorais/lean,leanprover/lean,avigad/lean,Kha/lean,sp3ctum/lean,soonhokong/lean,fpvandoorn/lean,digama0/lean,javra/lean,fgdorais/lean,soonhokong/lean-windows,soonhokong/lean-windows,levnach/lean,c-cube/lean,javra/lean,c-cube/lean,johoelzl/lean,leanprover-community/lean,fgdorais/lean,sp3ctum/lean,eigengrau/lean,johoelzl/lean,leanprover/lean,Kha/lean,leanprover/lean,levnach/lean,htzh/lean,avigad/lean,eigengrau/lean,soonhokong/lean-osx,leanprover-community/lean,dselsam/lean,leodemoura/lean,soonhokong/lean,sp3ctum/lean,htzh/lean,UlrikBuchholtz/lean,fpvandoorn/lean,soonhokong/lean,digama0/lean,avigad/lean,rlewis1988/lean,leanprover/lean,htzh/lean,soonhokong/lean,rlewis1988/lean,leodemoura/lean,leanprover/lean,htzh/lean,Kha/lean,leanprover-community/lean,dselsam/lean,c-cube/lean,dselsam/lean,eigengrau/lean,sp3ctum/lean,digama0/lean,fpvandoorn/lean2,UlrikBuchholtz/lean,fpvandoorn/lean,rlewis1988/lean,digama0/lean,fpvandoorn/lean2