refactor(library/kernel_bindings): remove level pair and list of level pairs from Lua API
refactor(library/kernel_bindings): remove level pair and list of level pairs from Lua API

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

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