Add John Cass to AUTHORS

Author: lafrech

AUTHORS

@@ -34,3 +34,4 @@ that much better:
 * Sibelius Seraphini - https://github.com/sibelius
 * Denny Huang - https://github.com/denny0223
 * Stefan Wojcik - https://github.com/wojcikstefan
+* John Cass - https://github.com/jcass77