Replace hexToRgb function to work with legacy mobile browsers

pyleds/templates/index.html

@@ -8,13 +8,10 @@
 
     <script type="text/javascript">
         function hexToRgb(value) {
-            var aRgbHex = value.substring(1).match(/.{1,2}/g);
+            return value.replace(/^#?([a-f\d])([a-f\d])([a-f\d])$/i
-            var aRgb = [
+                ,(m, r, g, b) => '#' + r + r + g + g + b + b)
-                parseInt(aRgbHex[0], 16),
+                .substring(1).match(/.{2}/g)
-                parseInt(aRgbHex[1], 16),
+                .map(x => parseInt(x, 16));
-                parseInt(aRgbHex[2], 16)
-            ];
-            return aRgb;
         }
 
         function show_loading(visible) {