Dino Dex First Refactor

Let me know when you have a few minutes.  I want to go over a few of the questions you had which I haven't yet done anything with.
Actually, this method is overriding the setter from the `attr_accessor`.  If you wrote ```
def weight_in_lbs=(weight_in_lbs)
  weight_in_lbs = weight_in_lbs
end```
you would have an infinite loop.

If you want to create a custom setter, make an `attr_reader` instead of an `attr_accessor` for `weight_in_lbs` and make the custom accessor there.