Try to ensure that Fragments are always move-constructible
During testing of the e14 build, we were seeing some performance issues with the Transfer tests. One possibility that was eliminated was that we were now using copy constructors instead of move constructors. I have made sure that the appropriate methods in QuickVec are marked noexcept, and have added explicit construction of the move constructors to Fragment.hh. This should through a compile-time error if Fragment ever violates the move-constructible constraints.