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/ColladaParser.cpp

@@ -2469,8 +2469,7 @@ void ColladaParser::CopyVertex(size_t currentVertex, size_t numOffsets, size_t n
     size_t baseOffset = currentPrimitive * numOffsets * numPoints + currentVertex * numOffsets;
 
     // don't overrun the boundaries of the index list
-    size_t maxIndexRequested = baseOffset + numOffsets - 1;
-    ai_assert(maxIndexRequested < indices.size());
+    ai_assert((baseOffset + numOffsets - 1) < indices.size());
 
     // extract per-vertex channels using the global per-vertex offset
     for (std::vector<InputChannel>::iterator it = pMesh->mPerVertexData.begin(); it != pMesh->mPerVertexData.end(); ++it)