Dino catalog

Basic CLI application as solution for dinodex exercise. @bwthomas how do I go about having it reviewed? 
... or you could do one of these:
```
@filters << ->(csvrow) { (csvrow[:weight] || 0) > 4000 }
```

```
@filters << ->(csvrow) { csvrow[:weight].to_i > 4000 }
```

Or even ...
```
@filters << ->(csvrow) { csvrow[:weight] > 4000 rescue false}
```