pong: fix undefined function

src/pong.ts

@@ -92,7 +92,7 @@ class PongCore {
     }
 
     start() {
-        setInterval(g_pong.loop, g_pong.timeout);
+        setInterval(this.loop, this.timeout);
     }
 
     reset() {
@@ -111,13 +111,13 @@ class PongCore {
     // Game loop
     loop() {
         // Reset of needed
-        if (this.gameover)
-            this.reset();
+        if (g_pong.gameover)
+            g_pong.reset();
 
-        this.simulate();
+        g_pong.simulate();
 
-        this.draw();
-        this.updatePageText();
+        g_pong.draw();
+        g_pong.updatePageText();
     }
 
     // Simulate game logic