feat(scoped_map): add operator<< to scoped_map for debugging
feat(scoped_map): add operator<< to scoped_map for debugging

leanprover/lean,leanprover-community/lean,htzh/lean,soonhokong/lean,fpvandoorn/lean,soonhokong/lean,sp3ctum/lean,soonhokong/lean-osx,johoelzl/lean,c-cube/lean,eigengrau/lean,rlewis1988/lean,UlrikBuchholtz/lean,leanprover-community/lean,fpvandoorn/lean2,johoelzl/lean,leanprover/lean,digama0/lean,soonhokong/travis_test,johoelzl/lean,soonhokong/lean-osx,leanprover/lean,UlrikBuchholtz/lean,rlewis1988/lean,dselsam/lean,dselsam/lean,fpvandoorn/lean,leanprover-community/lean,dselsam/lean,avigad/lean,digama0/lean,htzh/lean,UlrikBuchholtz/lean,codyroux/lean0.1,soonhokong/lean,javra/lean,levnach/lean,fpvandoorn/lean2,leanprover/lean,dselsam/lean,soonhokong/lean-osx,rlewis1988/lean,soonhokong/lean-windows,soonhokong/lean,soonhokong/lean,htzh/lean,levnach/lean,fgdorais/lean,javra/lean,c-cube/lean,leanprover-community/lean,leanprover/lean,soonhokong/travis_test,fpvandoorn/lean2,digama0/lean,leodemoura/lean,sp3ctum/lean,soonhokong/lean-osx,htzh/lean,leanprover-community/lean,Kha/lean,eigengrau/lean,johoelzl/lean,javra/lean,leodemoura/lean,Kha/lean,avigad/lean,digama0/lean,soonhokong/lean-windows,c-cube/lean,fgdorais/lean,fpvandoorn/lean,fpvandoorn/lean,leanprover/lean,javra/lean,Kha/lean,c-cube/lean,avigad/lean,htzh/lean,eigengrau/lean,johoelzl/lean,fgdorais/lean,leodemoura/lean,fpvandoorn/lean,fpvandoorn/lean2,Kha/lean,soonhokong/lean-windows,leodemoura/lean,c-cube/lean,digama0/lean,soonhokong/lean-windows,rlewis1988/lean,rlewis1988/lean,codyroux/lean0.1,eigengrau/lean,avigad/lean,levnach/lean,fgdorais/lean,soonhokong/lean-windows,sp3ctum/lean,avigad/lean,Kha/lean,rlewis1988/lean,digama0/lean,leanprover-community/lean,avigad/lean,dselsam/lean,eigengrau/lean,soonhokong/travis_test,dselsam/lean,leodemoura/lean,levnach/lean,soonhokong/travis_test,fgdorais/lean,sp3ctum/lean,codyroux/lean0.1,fpvandoorn/lean,UlrikBuchholtz/lean,johoelzl/lean,sp3ctum/lean,codyroux/lean0.1,soonhokong/lean-osx,fgdorais/lean,Kha/lean,leodemoura/lean,UlrikBuchholtz/lean,fpvandoorn/lean2,javra/lean,levnach/lean