This patch is a follow up to D2575/rP23728, D2596/rP23737, D2786/rP23752.
Currently champion elephants inflict a lot more damage than hero elephants, which seems odd, because it's typically the other way around. For comparison damage per second of other melee soldiers:
```
b , c , h
cavalry axeman : 9.2 , 18.4 , 36.8
cavalry spearman : 5.5 , 11 , 22
cavalry swordsman : 8.7 , 17.3 , 34.7
```
[EDIT] This patch:
* keeps champion elephant damage as is (i.e. per second 13 hack + 100 crush);
* changes hero elephant damage, costs, and loot to twice the champion's;
* reduces champion elephant crush armour to 20 (same as other champions; hero elephants already have the same as other heroes (25) and elephant archers the same as citizens (15));
* removes 5% walk speed penalty, to give melee elephants the same movement speed as elephant archers;
* increases elephant archer vision from 92 to 100 (same as melee champion and hero elephants);
* disables elephant archer slaughter attack, because they can't gather resources anyway;
* removed the bonus attack damage from `template_unit_fauna_hunt_defensive_elephant.xml`; other animals don't have bonuses either, nor do elephant soldiers.
See also D2595 and D2852.