refactor(library/tactic): cleanup
refactor(library/tactic): cleanup

Signed-off-by: Leonardo de Moura <7610bae85f2b530654cc716772f1fe653373e892@microsoft.com>

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