pyjsonfix

Added a bunch of unit tests. Run with ./run_tests.py

Fixed some issues with lists. Wasn't properly adding a null if the first element was empty, and wasn't detecting the end of a list as an end of a number

Fixed it breaking when starting a key with a _, fixed it needlessly escaping 's, and made it properly explode when given a key starting with a number

Made errors raise ValueError exceptions

Lots of refactoring and a couple bug fixes