fix double event registering

Took 4 minutes

src/web/WebWebSocketHandler.ts

@@ -29,6 +29,14 @@ export class WebWebSocketHandler {
     }
 
     public static registerForEvent(event: WebSocketEvent, fn: (payload: WebSocketPayload) => void) {
+        for( let e of WebWebSocketHandler.eventRegister )
+        {
+            if (e.fn == fn) {
+                console.log("Event fn already registered");
+                return;
+            }
+        }
+
         WebWebSocketHandler.eventRegister.push({event: event, fn: fn});
     }