Code review comment for lp:~verifypn-cpn/verifypn/unfold-improve

There are some warnings to be fixed:

PetriEngine/Colored/ColoredPetriNetBuilder.cpp:31:34: warning: moving a
      temporary object prevents copy elision [-Wpessimizing-move]
            _places.emplace_back(std::move(Colored::Place {name, type, t...
                                 ^
PetriEngine/Colored/ColoredPetriNetBuilder.cpp:31:34: note: remove std::move
      call here
  ..._places.emplace_back(std::move(Colored::Place {name, type, tokens}));
                          ^~~~~~~~~~ ~
PetriEngine/Colored/ColoredPetriNetBuilder.cpp:46:39: warning: moving a
      temporary object prevents copy elision [-Wpessimizing-move]
            _transitions.emplace_back(std::move(Colored::Transition {nam...
                                      ^
PetriEngine/Colored/ColoredPetriNetBuilder.cpp:46:39: note: remove std::move
      call here
  ..._transitions.emplace_back(std::move(Colored::Transition {name, guard}));
                               ^~~~~~~~~~ ~