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.
Another way to get rid of the shadow variable would be to not bother assigning:

```
def print_dino_facts(name)
  @dinosaurs.detect { |dino| dino.name == name }.to_s
end