Modules are commands or full programs (anything can be made into a module
that can return int type) should go here. Note, modules do not (can not)
update or read cliuser_t.

Stuff that needs to write to the user structures contained in scli.h should 
be made as built-in commands, not modules, but there are very few times when
you would want to do that.

See the README file in the bdsh root directory for a quick overview of how to
write a new command, or convert an existig stand-alone program into a module
for BDSH.