message: Remove return after throw
  Fixes warning about unreachable return. (`-Wunreachable-code-return`)
diff: @@ -232,7 +232,6 @@ void StructureManager::addStructure(Structure* st, Tile* t)
  if (mStructureTileTable.find(st) != mStructureTileTable.end())
  {
  throw std::runtime_error("StructureManager::addStructure(): Attempting to add a Structure that is already managed!");
  - return;
  }
  // Remove things from tile only if we know we're adding a structure.
  