Added FINE_LOCATION permission checks. Added location update and save logic.

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

@@ -1,22 +1,25 @@
 <?xml version="1.0" encoding="utf-8"?>
 <menu xmlns:android="http://schemas.android.com/apk/res/android">
 
+    <item
+        android:id="@+id/update_location"
+        android:title="@string/menu_update_location" />
     <item
         android:id="@+id/fetch_trans"
-        android:title="Fetch Transmitters" />
+        android:title="@string/menu_fetch_transmitters" />
     <item
         android:id="@+id/save_to_db"
-        android:title="Save to DB" />
+        android:title="@string/menu_save_to_db" />
     <item
         android:id="@+id/load_from_db"
-        android:title="Load from DB" />
+        android:title="@string/menu_load_from_db" />
     <item
         android:id="@+id/fetch_tle"
-        android:title="Fetch TLE" />
+        android:title="@string/menu_fetch_tle" />
     <item
         android:id="@+id/load_tle"
-        android:title="Load TLE" />
+        android:title="@string/menu_load_tle" />
     <item
         android:id="@+id/action_exit"
-        android:title="Exit" />
+        android:title="@string/menu_exit" />
 </menu>