Introduce methods distanceTo() and dot() to Vector2 and Vector3

docs/api/vector2.md

 
 The length of the vector.
 
+### dot
+
+`vector.dot(v: Vector2): number`
+
+Compute the dot product of `this` and `v`.
+
+**Arguments**
+
+* `v: Vector2`. A vector.
+
+**Returns**
+
+The dot product of the vectors.
+
+### distanceTo
+
+`vector.distanceTo(v: Vector2): number`
+
+Compute the distance between points `this` and `v`.
+
+**Arguments**
+
+* `v: Vector2`. A vector / point.
+
+**Returns**
+
+The distance between the points.
+
 ### directionTo
 
 `vector.directionTo(v: Vector2): Vector2`

docs/api/vector3.md

 
 The length of the vector.
 
+### dot
+
+`vector.dot(v: Vector3): number`
+
+Compute the dot product of `this` and `v`.
+
+**Arguments**
+
+* `v: Vector3`. A vector.
+
+**Returns**
+
+The dot product of the vectors.
+
+### distanceTo
+
+`vector.distanceTo(v: Vector3): number`
+
+Compute the distance between points `this` and `v`.
+
+**Arguments**
+
+* `v: Vector3`. A vector / point.
+
+**Returns**
+
+The distance between the points.
+
 ### directionTo
 
 `vector.directionTo(v: Vector3): Vector3`

src/geometry/vector2.ts

     }
 
     /**
+     * Compute the dot product of this and v
+     * @param v a vector
+     * @returns the dot product of the vectors
+     */
+    dot(v: Vector2): number
+    {
+        return this.x * v.x + this.y * v.y;
+    }
+
+    /**
+     * Compute the distance between points this and v
+     * @param v a vector / point
+     * @returns the distance between the points
+     */
+    distanceTo(v: Vector2): number
+    {
+        const dx = this.x - v.x;
+        const dy = this.y - v.y;
+
+        return Math.sqrt(dx*dx + dy*dy);
+    }
+
+    /**
      * Compute the direction from this to v
      * @param v a vector
      * @returns a new unit vector pointing to v from this

src/geometry/vector3.ts

     }
 
     /**
+     * Compute the dot product of this and v
+     * @param v a vector
+     * @returns the dot product of the vectors
+     */
+    dot(v: Vector3): number
+    {
+        return this.x * v.x + this.y * v.y + this.z * v.z;
+    }
+
+    /**
+     * Compute the distance between points this and v
+     * @param v a vector / point
+     * @returns the distance between the points
+     */
+    distanceTo(v: Vector3): number
+    {
+        const dx = this.x - v.x;
+        const dy = this.y - v.y;
+        const dz = this.z - v.z;
+
+        return Math.sqrt(dx*dx + dy*dy + dz*dz);
+    }
+
+    /**
      * Compute the direction from this to v
      * @param v a vector
      * @returns a new unit vector pointing to v from this