* fix serialization
Was incorrect before. The only flags are if any data in the FrameStats has changed, you write them again. Velocities also do not use dirty flags for their values, they use a flag to determine if their velocity if zero or non-zero. if any velocity changes, re-write FrameStats.
Tested that 2 players can see each other move as before, enemies move as before and players racing is identical as before.
* Update HavokVehiclePhysicsComponent.cpp
