Increase update interval to 1500ms

speedtest.js

@@ -343,7 +343,7 @@ Speedtest.prototype = {
       function() {
         this.worker.postMessage("status");
       }.bind(this),
-      200
+      1500
     );
     if (this._state == 1)
         throw "When using multiple points of test, you must call selectServer before starting the test";