Code warning cleanup and add GPL license header to all CPP files

UpdateCallback.cpp

@@ -1,3 +1,22 @@
+/*
+ * This file is part of vimix - video live mixer
+ *
+ * **Copyright** (C) 2020-2021 Bruno Herbelin <bruno.herbelin@gmail.com>
+ *
+ * This program 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.
+ *
+ * This program 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 this program. If not, see <https://www.gnu.org/licenses/>.
+**/
+
 #include "UpdateCallback.h"
 
 #include "defines.h"
@@ -16,7 +35,7 @@ CopyCallback::CopyCallback(Node *target) : UpdateCallback(), target_(target)
 
 }
 
-void CopyCallback::update(Node *n, float dt)
+void CopyCallback::update(Node *n, float)
 {
     n->copyTransform(target_);
     finished_ = true;
@@ -82,7 +101,7 @@ void RotateToCallback::update(Node *n, float dt)
 }
 
 BounceScaleCallback::BounceScaleCallback(float scale) : UpdateCallback(),
-    duration_(100.f), progress_(0.f), initialized_(false), scale_(scale)
+    initialized_(false), duration_(100.f), scale_(scale), progress_(0.f)
 {
 
 }