feat(emacs/lean-server): kill the server before emacs exit
feat(emacs/lean-server): kill the server before emacs exit

Close #138

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