Add helper method of checking for a help flag.

[digitalghost-dev]

All provided commands are ran through the validation functions in cmd/validateargs.go file.

Currently, in v0.7.0, both the pokemon and types commands are checked for a -h or --help flag in `os.Args[2].

To reduce redundancy, a helper method can be created then used throughout the validation functions. This will continue to provide clean code when new commands are added.

For example:

func handleHelpFlag(args []string) {
  if len(args) == 3 && (args[2] == "-h" || args[2] == "--help") {
    flag.Usage()
  if flag.Lookup("test.v") == nil {
    os.Exit(0)
	}
    }
}