First Dino Dex Program

I have it set up right now to just run the code in the Main class, and it prints the results to the console.
Name this `to_json`. Since we're not really saving any complexity, remove the local var:

```
def to_json(include_filter = false)
  if include_filter
    @dinosaurs_filtered.to_json
  else
    @dinosaurs.to_json
  end
end