Improve formatting of command line help

For command line parameters where there is both a short or a long version of the same option, the short and long version should be comma separated. This is similar to how many command line tools display help or in man pages.

Current output:

    -h                                  Display this message and exit

    --help                              Display this message and exit

Suggested output:

    -h, --help                          Display this message and exit