optimization:   GVTManager::getGVTInfo() is called every time a message is created.   callgrind results show that Mattern GVT's use of ostringstream   in this function was taking up 4% of the entire simulation.   replacing with sprintf() takes us down to less than 1%
optimization:
  GVTManager::getGVTInfo() is called every time a message is created.
  callgrind results show that Mattern GVT's use of ostringstream
  in this function was taking up 4% of the entire simulation.
  replacing with sprintf() takes us down to less than 1%

wilseypa/warped,wilseypa/warped