fix trivial warnings

mainly unused parameter and unused function
some parameters are indeed used in a debug built, I used the
(void)(param) trick
warnings reported by clang 4

code/IRRLoader.cpp

@@ -394,7 +394,7 @@ void IRRImporter::ComputeAnimations(Node* root, aiNode* real, std::vector<aiNode
                 angles[1] %= 360;
                 angles[2] %= 360;
 
-                if ((angles[0]*angles[1]) && (angles[1]*angles[2]))
+                if ( bool(angles[0]*angles[1]) && bool(angles[1]*angles[2]) )
                 {
                     FindSuitableMultiple(angles[0]);
                     FindSuitableMultiple(angles[1]);