Cleanup, copyright notice, GPL headers

kubo_wall.c

@@ -1,3 +1,21 @@
+/*
+ * Copyright Luka Jankovic 2025
+ *
+ * This file is part of Kubo.
+ *
+ * Kubo is free software: you can redistribute it and/or modify it under the
+ * terms of the GNU General Public License as published by the Free Software
+ * Foundation, either version 3 of the License, or (at your option) any later
+ * version.
+ *
+ * Kubo is distributed in the hope that it will be useful, but WITHOUT ANY
+ * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
+ * A PARTICULAR PURPOSE. See the GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * Kubo. If not, see <https://www.gnu.org/licenses/>.
+ */
+
 #include "kubo_wall.h"
 
 struct kubo_wall *kubo_wall_init() {