Server/utils

## Check out
the Utils class especially and also what I did to the login, register, join, create, list games handlers. I think this will make the rest really easy. _(The games and users lists are in the utils class as static fields)_

## Files Added
- Two objects to make Gson serialization easier
- A Utils class that has tons of neat methods
- A client object that represents the person sending us requests

Jeremy: sorry I overwrote your login and register methods.