Parse argv, setting options and invoking commands when defined.

The default expectation is that the arguments are from node and have the application as argv[0] and the script being run in argv[1], with user parameters after that.

Examples:

 program.parse(process.argv);
 program.parse(); // implicitly use process.argv and auto-detect node vs electron conventions
 program.parse(my-args, { from: 'user' }); // just user supplied arguments, nothing special about argv[0]