Reference duplicated of RouteMessages into the RouteMessagePool

[jordi]

From Max:

I think you should check if the RouteMesssage that should be freed is 
already in the messages stack in RouteMessagePoolImpl.
For example I freed my RouteMessage after I called 
endpoint.schedule(...){... calls freeMessage too...} and because of that 
the reference of one RouteMessage were two times on the messages stack.
So the first message I tried to send next vanished because the second 
message I send overwrited the first sended message.

[jordi]

To avoid innecessary comparisons, we left on the hands of the developer to have the absolute control for when and where to free a RouteMessage?. Therefore, it is not a but in the PlanetSim, is a (in)correct sentence use.