Change the multibyte character set support so that

Change the multibyte character set support so that
Kanji support is one case of multibyte character
support, rather than being a specific case in
single byte character support.

This allows us to add Big5 Chinese support (code page 950)
and Korean Hangul support (code page 949) at very little
cost. Also allows us to easily add future multibyte
code pages.

Makefile: Added codepages 949, 950 as we now support more multibyte
codepages.
asyncdns.c: Fixed problem with child being re-spawned when parent killed.
charcnv.c
charset.c
client.c
clitar.c
kanji.c
kanji.h
smb.h
util.c
loadparm.c: Generic multibyte codepage support (adding Big5 Chinese
            and Korean Hangul).
nmbd.c: Fixed problem with child being re-spawned when parent killed.
mangle.c: Modified str_checksum so that first 15 characters have more
          effect on outcome. This helps with short name mangling as
          most 'long' names are still shorter than 15 chars (bug was
          foobar_mng and foobar_sum would hash to the same value, with
          the modified code they hash differently.
Jeremy.