Accept --help and --version, and lots of syntactic clean-up.
Use consistent indentation, two spaces per level.
(scriptversion): New variable.
Change initializations like `variable=""' to `variable='.
(usage): New variable.
Use `test', not `['.
Use `test -z "$var"', not `[ x"$var" = x ]'.
Use `test -n "$var"', not `[ x"$var" != x ]'.
Alphabetize case entries.
Accept --help and --version options.
Remove unnecessary `else :' clauses.
Add a `Local variables' eval block to help emacs users update
the time-stamp variable added above.
Mostly from Karl Berry.