Pull requests are welcome.
Please use "phpfmt" to ensure consistent formatting.
Before you do a PR, you should ensure any new functionality has test cases and that all existing tests are succeeding.
Since this project is a single file application, you must ensure that classes are loaded in the correct order. This is only important for the "extends" and "implements" relations. The 'build.php' script appends the classes in alphabetical order (directories first). The path of the class that is extended or implemented (parent) must be above the extending or implementing (child) class when listing the contents of the 'src' directory in this order. If you get this order wrong you will see the build will fail with a "Class not found" error message. The solution is to rename the child class so that it starts with a later letter in the alphabet than the parent class or that you move the parent class to a subdirectory (directories are scanned first).