Improve opt parsing, and distinguish long from short.

Improve opt parsing, and distinguish long from short.

In several cases, two different long options map to the same short
option.  So e.g. you could give '--brief' and it would be interpreted
as '--bitmap'.  That isn't really good.

So for every shared short option, define an option number and return
that for the long option instead.  Then always check for both the
short and long options.

Also give some bugs like " mode == 'G'" which should be '== GROW'.

Signed-off-by: NeilBrown <neilb@suse.de>