started skeleton and zombie, added GUI and menu system

Signed-off-by: Pascal Syma <pascal@syma.dev>

src/entities/Enemys/Zombie.js

@@ -0,0 +1,21 @@
+/*
+ * Copyright (c) 2020. Antonio Martinez Casadesus and Pascal Syma.
+ * All rights reserved.
+ */
+
+import Enemy from "./Enemy";
+
+export default class Zombie extends Enemy {
+
+    constructor(scene, item) {
+        super(scene, item, "zombie");
+    }
+
+
+    turnedActive() {
+        super.turnedActive();
+        const vel = this.spawnPoint.properties.filter(obj => obj.name === "velocity")[0].value;
+        this.body.velocity.x = vel;
+
+    }
+}