PHP depreciation fixes

This removes deprecation warnings from PHP 8.4. Thanks to @xergio for the contribution!

This also removes the abandoned Phony library from the unit tests; PHPUnit's built-in mocking is used instead. Code has also been listed to PSR-2 standards.

As a reminder, I cannot guarantee this library is or will be functional as I am not currently using the X API. Get in touch if you are willing and able to take over active maintenance.