Remove double-dash parameters from mapArgs

Should be merged after pull request #4281
("Add `-version` option to get just the version #4281"),
because is changed "--help" to "-help".

Checked that grep of 'mapArgs.count("--' returned only
three places that are fixed by pull request #4281.
Merge pull request #4193

71aaff3 Remove double-dash parameters from mapArgs (Kosta Zertsekel)