fix(emacs/lean-server): use process-query-on-exit-flag to kill lean-server automatically on exit
fix(emacs/lean-server): use process-query-on-exit-flag to kill
lean-server automatically on exit

To fix a problem mentioned in #147

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