[engine] Stop when attacked

[SFault]

Would it be possible to have unit to stop the automatic movement after some lurker attacks it? This is really big deal in big maps with fast or ambush units and shroud (or something else that prevents undo). I have a unit that needs to travel a long way. Then, some lurker comes and attacks the unit. My unit keeps on traveling and I lose the chance to attack back. It would be really great that I could choose an option (although I don't see why I wouldn't want it to be chosen) that would forget the path and make the unit to stop if it's been attacked.