sync experimental with trunk

git-svn-id: https://foundry.supelec.fr/svn/luatex/trunk@4847 0b2b3880-5936-4365-a048-eb17d2e5a6bf
sync experimental with trunk -- added patches for standard lua and standard luajit 

git-svn-id: https://foundry.supelec.fr/svn/luatex/trunk@4848 0b2b3880-5936-4365-a048-eb17d2e5a6bf
restored correct  texmfmp.c and texmfmp.h (thank to A. Kakuto)

git-svn-id: https://foundry.supelec.fr/svn/luatex/trunk@4849 0b2b3880-5936-4365-a048-eb17d2e5a6bf
fixed patch-02-lstring 

git-svn-id: https://foundry.supelec.fr/svn/luatex/trunk@4850 0b2b3880-5936-4365-a048-eb17d2e5a6bf
fixed several things about luajittex hash; updated the manual

git-svn-id: https://foundry.supelec.fr/svn/luatex/trunk@4857 0b2b3880-5936-4365-a048-eb17d2e5a6bf
Fixed luajittex_choose_hash_function (A. Kakuto)

git-svn-id: https://foundry.supelec.fr/svn/luatex/trunk@4859 0b2b3880-5936-4365-a048-eb17d2e5a6bf