This patch separates chariots from cavalry by creating the following templates:
```
template_unit_champion_chariot.xml
template_unit_champion_chariot_archer.xml
template_unit_champion_chariot_javelineer.xml
template_unit_hero_chariot.xml
template_unit_hero_chariot_archer.xml
template_unit_hero_chariot_javelineer.xml
```
This allows further differentiation. Chariots:
* no longer have a Cavalry class, which means they don't benefit from cavalry auras and technologies (neither do dogs and elephants);
* keep the same attacks and movement speed as cavalry;
* have slightly more armour than cavalry (champion +1/+3/+0, hero +0/+2/+0);
* champion chariots have double health but cost more:
```
inf , cav , cha , ele
food : 80 , 150 , 200 , 300
wood : 60 , 80 , 160 ,
metal : 80 , 100 , 120 , 200
population : 1 , 1 , 2 , 3
time : 20 , 30 , 30 , 30
health : 100 , 240 , 500 , 750
experience : 150 , 200 , 250 , 300
```
As you can see champion chariots have values something in between cavalry and elephants.
While at it, archer attack sounds are also cleaned up, now defined in the `*_archer.xml` templates, rather than their grandparents (cf. `*_javelineer.xml` templates).