allows utf8 identifiers in lua (as is in standard luajit)

git-svn-id: https://foundry.supelec.fr/svn/luatex/trunk@4796 0b2b3880-5936-4365-a048-eb17d2e5a6bf
allows utf8 identifiers in lua (as is in standard luajit) -- patch

git-svn-id: https://foundry.supelec.fr/svn/luatex/trunk@4797 0b2b3880-5936-4365-a048-eb17d2e5a6bf
Fixed luaopen_bit32 declaration (Akira Kakuto)

git-svn-id: https://foundry.supelec.fr/svn/luatex/trunk@4800 0b2b3880-5936-4365-a048-eb17d2e5a6bf
replace couple_nodes with try_couple_nodes to manage null nodes

git-svn-id: https://foundry.supelec.fr/svn/luatex/trunk@4804 0b2b3880-5936-4365-a048-eb17d2e5a6bf