feat(emacs/lean-type): implement lean-set-option and lean-eval-cmd
feat(emacs/lean-type): implement lean-set-option and lean-eval-cmd

close #55

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