largely rewrote smbpasswd so that the code is understandable. This

largely rewrote smbpasswd so that the code is understandable. This
should allow us to call a function in swat rather than piping to
smbpasswd.

while doing this I also fixed quite a few "const char *" versus "char *" issues
that cropped up while using const to track down bugs in the code. This
led to changes in several generic functions.

The smbpasswd changes should be correct but they have not been
extensively tested. At least if I have introduced bugs then we should
be able to fix them more easily than before.