Major updates to drawer header layout. Added extension methods for doubles in shared preferences. Code cleanup.

app/src/main/res/menu/drawer_menu.xml

@@ -12,10 +12,6 @@
             android:title="@string/menu_map" />
     </group>
 
-    <item
-        android:id="@+id/nav_settings"
-        android:title="@string/menu_settings" />
-
     <item android:title="@string/menu_about">
         <menu>
             <item