fix damage text rounding errors when accumulating damage

This fixes MG reporting wrong damage when accumulated after passing through a wall (or similar situations where damage is not a whole number) while keeping rounding behavior for weapons like mortar.

I used MinceR's idea of multiplying the damage by 100 and sending the decimal part inside the short instead of using float to keep bandwidth the same.

Now that i think about it, this could cause trouble if the damage dealt is higher than 655 (because 656*100 won't fit in short). However health and armor max is 200 so it shouldn't happen unless we start sending damage text for vehicles as well.