feat: quaternion

src/main.ts

@@ -1,3 +1,4 @@
 export * from "./multi-pid";
 export * from "./pid";
 export * from "./vec";
+export * from "./quaternion";

src/vec.ts

@@ -62,9 +62,3 @@ export class Vec3 {
     return this.mul(math.cos(theta)).add(relativeDir.mul(math.sin(theta)));
   }
 }
-
-export interface Quaternion {
-  x: number;
-  y: number;
-  z: number;
-}