add wojcikstefan to authors

Author: wojcikstefan

AUTHORS

@@ -33,3 +33,4 @@ that much better:
 * Bruno Belarmino - https://github.com/brunobelarmino
 * Sibelius Seraphini - https://github.com/sibelius
 * Denny Huang - https://github.com/denny0223
+* Stefan Wojcik - https://github.com/wojcikstefan