switched over to a new method of handling uppercase/lowercase mappings

switched over to a new method of handling uppercase/lowercase mappings
for unicode strings. The new method relies on 3 files that are mmap'd
at startup to provide the mapping tables. The upcase.dat and
lowcase.dat tables should be the same on all systems. The valid.dat
table says what characters are valid in 8.3 names, and differs between
systems. I'm committing the japanese valid.dat here, in future we need
some way of automatically installing and choosing a appropriate table.

This commit also adds my mini tdb based gettext replacement in
intl/lang_tdb.c. I have not enabled this yet and have not removed the
old gettext code as the new code is still being looked at by Monyo.

Right now the code assumes that the upcase.dat, lowcase.dat and
valid.dat files are installed in the Samba lib directory. That is not
a good choice, but I'll leave them there until we work out the new
install directory structure for Samba 3.0.

simo - please look at the isvalid_w() function and think about using
it in your new mangling code. That should be the final step to
correctly passing the chargen test code from monyo.
(This used to be commit 1c221994f118dd542a158b2db51e07d04d0e9314)