another fix for issue 857

git-svn-id: https://foundry.supelec.fr/svn/luatex/branches/experimental@4677 0b2b3880-5936-4365-a048-eb17d2e5a6bf
fix issue 869

git-svn-id: https://foundry.supelec.fr/svn/luatex/branches/experimental@4678 0b2b3880-5936-4365-a048-eb17d2e5a6bf
New trunk with the experimental, kill-att and ex-glyph branches

git-svn-id: https://foundry.supelec.fr/svn/luatex/branches/experimental@4679 0b2b3880-5936-4365-a048-eb17d2e5a6bf