make debris damage proportional to unit size/dps, for small units

[Bluestone]

see ​http://springrts.com/phpbb/viewtopic.php?f=44&t=32067&p=557228#p557228 for details

[Floris]

Finally. I've noted this before but didnt want to go through all the effort klapmongool had to do in order to get this some attention.

[Bluestone]

@Floris: I regard your comment as inappropriate, especially when made on this location.

All that was required from klap was a clear statement of the problem. That is simply the _normal_ requirement of any bug report, in any situation.

Furthermore, klap got a near instant response, an hour of my time, an explanation of exactly the problem was and an explanation of what would change as a result. If you regard that as a substandard response in a piece of free software then you are living in a dreamworld.

[Bluestone]

set to math.random(15,35), since attackDefID is nil for debris damage