added compass button and coupled its transform:rotate style attribute with the POV heading value

public/static/js/game.js

@@ -382,6 +382,10 @@
 
             // needs to be set visible after the show guess map hid it in mobile view
             document.getElementById("navigation").style.visibility = 'visible';
+
+            // update the compass
+            const heading = Game.panorama.getPov().heading;
+            document.getElementById("compass").style.transform = "rotate(" + heading + "deg)";
         },
 
         handleErrorResponse: function (error) {
@@ -858,6 +862,9 @@
 
     Game.panorama.addListener('pov_changed', function () {
         Game.rewriteGoogleLink();
+
+        const heading = Game.panorama.getPov().heading;
+        document.getElementById("compass").style.transform = "rotate(" + heading + "deg)";
     });
 
     if (COOKIES_CONSENT) {