Dino dex 2nd Refactor

DinoDex refactor based on comments from previous pull request.

The DinoDex has a command line interface. Run the "main.rb" script to initialize the CLI.
You want to avoid `case` statements. You can set up a mapping from command to method and invoke them that way. For example `actions['help'] = method(print_help_menu)`. Then invoke the method using `call` like: `actions[user_input].call if defined(actions[user_input])`. You can pass method arguments to `call` if need be. This is one way to do it, you are free to explore other ways.