Add convenience method to reverse a bezier curve

src/bezier.js

@@ -1998,6 +1998,14 @@ class Bezier {
     return `<[${this.points[0].x},${this.points[0].y}], [${this.points[1].x},${this.points[1].y}], [${this.points[2].x},${this.points[2].y}], [${this.points[3].x},${this.points[3].y}]`
   }
 
+  reverse() {
+    return new Bezier(
+      this.points[3].x, this.points[3].y,
+      this.points[2].x, this.points[2].y,
+      this.points[1].x, this.points[1].y,
+      this.points[0].x, this.points[0].y)
+  }
+
 }
 
 export { Bezier };