Add php-refactor-mode

I am the creator and maintainer of [php-refactor-mode](https://github.com/keelerm84/php-refactor-mode.el).  This is a minor mode for providing common refactoring support for PHP using the [php-refactoring-browser](https://github.com/QafooLabs/php-refactoring-browser) command line utility.

This is the first time I've submitted a package to melpa so please let me know if there is anything you would like me to adjust regarding this package.  Thank you.