Fixed syntax error in index.php

Signed-off-by: Darren Hill <dchill42@gmail.com>
Fixed syntax errors, cleaned logic, and improved testability for Xylophone.php

Signed-off-by: Darren Hill <dchill42@gmail.com>
Established initial Xylophone unit test

Signed-off-by: Darren Hill <dchill42@gmail.com>