Code review and changes for my Random Number Generator

If you recall, last week, I made a random number generator as part of the Treehouse JS Basics course. Well, after fnenu did code review, I realized I had some weird stuff going on there!  

The easiest way to explain the mistakes I made is to see the diff.  

This seems like a lot more code, and I'm sure there are ways to slim it down. (Pull requests welcome!)