Fixed build warnings on MSVC14 x64 in the COB format sources.

code/COBLoader.cpp

@@ -181,7 +181,7 @@ void COBImporter::InternReadFile( const std::string& pFile,
         if (n->type == Node::TYPE_MESH) {
             Mesh& mesh = (Mesh&)(*n.get());
             if (mesh.vertex_positions.size() && mesh.texture_coords.size()) {
-                pScene->mNumMeshes += mesh.temp_map.size();
+                pScene->mNumMeshes += static_cast<unsigned int>(mesh.temp_map.size());
             }
         }
     }