Added extra settings for Lollipop devices

Two settings have been added:
- Notification visibility - allows the notification to be made visible on a
secure lock screen
- Color - used to set the color of the notification circle that contains the
icon

www/background-mode.js

@@ -65,7 +65,9 @@ exports._defaults = {
     text:   'Doing heavy tasks.',
     ticker: 'App is running in background',
     resume: true,
-    silent: false
+    silent: false,
+    isPublic: false,
+    color: ""
 };