Audit mv(1)

1) Make argument-naming consistent with other tools (cp(1), ...)
2) style fixes
3) usage() fix
4) BUGFIX: Probably from the old non-arg.h days, the directory-
   check was only done when argc > 3, but with arg.h, this ignores
   the case when 3 arguments were given.
   This is actually a pretty serious issue and I'm glad it's fixed.
5) Moreover, be more verbose when stat() fails and make it clearer
   what the hell is going on at this checkpoint.

README

@@ -47,7 +47,7 @@ The following tools are implemented ('*' == finished, '#' == UTF-8 support,
 =*  mkdir           yes                          none
 =*| mkfifo          yes                          none
 =*  mktemp          non-posix                    none
-=*  mv              yes                          none (-i)
+=*| mv              yes                          none (-i)
 =*| nice            yes                          none
 =   nl              no                           -d, -f, -h, -l, -p
 =*| nohup           yes                          none