Added support to display battle Animations in battle scripts.

I'll use that to display nicer effects on the different attacks.

I also fixed the bindings of Battle Ammo described wrongly as a child of BattleActor.

Fixes #222
Prettify a bit the characters attack animations.

- I added some dust when a character is moving.
- Added a WIP slash animation when Bronann strikes.
- Added a new animation when Bronann does a Forward thrust.