Unit Testing

@zonuexe `php-runtime.el` is a useful Emacs Lisp project that I feel like I can work on in my spare time given my current health situation. Like all good projects it needs a good suite of unit tests. In order to learn more about the code I am currently working on a test suite using ERT, and hopefully I will soon have a branch of patches to submit. I just wanted to let you know that is a part of the project I am working on.