feat(bin/linja): linja calls lean if project does not exist
feat(bin/linja): linja calls lean if project does not exist

close #110

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