Refactorings, add support for scenes and rooms

Hey it's me again!  Remember how I asked about if you were open to more refactorings?  Well here it is!  
Before you look at his huge pull request and freak out, let me give you a little background on what we did and why.  :)

There are a handful of us at work that like to get together once a week at lunch and try to sharpen our development skills.  We saw this project and thought it was really cool because it had a good foundation and we really like the Vera as a home automation device.  We also saw that this project was lacking some testing and it's something we wanted to get better at and felt we could contribute.  Through the process of testing we also applied refactorings, really trying to increase readability and testability. (It now has 94% test coverage!)

We also added a few little features like the ability to list scenes and run them along with listing the room labels.

I hope you find this a useful contribution.  We really had a great time going through this and we learned a lot.

I apologize for doing this in one huge pull request.  If you have issues or questions with any of it, please let me know and I'd be happy to work through any of it with you.  Thanks!
Calling load_rooms and load_scenes here is a bit kludgy, and I admit I'm not a fan of using a class variable to store the rooms (or filters etc), that pattern breaks down when you have to communicate with more than one Vera device, which is a use case for me. Thus far all of my other commentary is just nits, but this is an actual important detail.