Dino catalog

Basic CLI application as solution for dinodex exercise. @bwthomas how do I go about having it reviewed? 
Understood. There the explicit return was to reinforce the comment above, allowing potential new logic to be added there without having to worry about its incidental return value. (Implicit return values are great for short and sweet methods but constitute "negative information" when later it may not be clear it wasn't incidental after all.)