Add note to use -h for more detail in Usage.

[richardhsu]

When you type naarad it will generate a simple usage report:

Usage: 
 To generate a diff report      : naarad -d report1 report2 -o <output_location> -c <optional: config-file> -e <optional: turn on exit code>
 To generate an analysis report : naarad -i <input_location> -o <output_location> -c <optional: config_file> -e <optional: turn on exit code> -n <optional: disable plotting of images>

We should add a quick note so users can know to type -h for more detail.

Proposing:

For more detail and help : naarad -h

Usage: 
 To generate a diff report      : naarad -d report1 report2 -o <output_location> -c <optional: config-file> -e <optional: turn on exit code>
 To generate an analysis report : naarad -i <input_location> -o <output_location> -c <optional: config_file> -e <optional: turn on exit code> -n <optional: disable plotting of images>
 For more detail and help       : naarad -h