CodeQuality improvements

Several small code improvements based on a cppcheck result

code/LWSLoader.cpp

@@ -450,7 +450,7 @@ void LWSImporter::BuildGraph(aiNode* nd, LWS::NodeDesc& src, std::vector<Attachm
 	}
 
 	// Add children
-	if (src.children.size()) {
+	if (!src.children.empty()) {
 		nd->mChildren = new aiNode*[src.children.size()];
 		for (std::list<LWS::NodeDesc*>::iterator it = src.children.begin(); it != src.children.end(); ++it) {
 			aiNode* ndd = nd->mChildren[nd->mNumChildren++] = new aiNode();