Implement directional influence (#43)

Reviewed-on: #43
Co-authored-by: Álex Román Núñez <eirexe@eirteam.moe>

src/fighter/attack/mod.rs

@@ -1,6 +1,7 @@
 use std::collections::{HashMap, VecDeque};
 
 mod reaction;
+pub mod directional_influence;
 
 use bevy::ecs::entity::{EntityMapper, MapEntities};
 use bevy::prelude::*;
@@ -42,7 +43,7 @@ pub enum HitReactionKind {
 
 #[derive(Debug, Hash, Clone)]
 pub struct FighterHitReaction {
-    pub launch_velocity: FGVec2,
+    pub launch_velocity: FGi32,
     pub launch_angle: FGi32,
     pub hitstop_frames: HitStop,
     pub hitstun_frames: u32,