Add a menu item to start/stop gps.

MyTracks/res/menu/track_list.xml

@@ -21,6 +21,11 @@ limitations under the License.
     android:id="@+id/track_list_search"
     android:showAsAction="ifRoom|collapseActionView"
     android:title="@string/menu_search"/>
+  <item
+    android:icon="@drawable/menu_start_gps"
+    android:id="@+id/track_list_start_gps"
+    android:showAsAction="ifRoom"
+    android:title="@string/menu_start_gps"/>
   <item
     android:icon="@drawable/menu_import"
     android:id="@+id/track_list_import"

MyTracks/res/values/strings.xml

@@ -1171,6 +1171,18 @@ limitations under the License.
       Character limit: ~20 (1 line)">
     Split frequency
   </string>
+  <string name="menu_start_gps"
+    translation_description="In the menu, to start the GPS receiver on the phone.
+
+      Character limit: ~20 (1 line)">
+    Start GPS
+  </string>
+  <string name="menu_stop_gps"
+    translation_description="In the menu, to stop the GPS receiver on the phone.
+
+      Character limit: ~20 (1 line)">
+    Stop GPS
+  </string>
   <string name="menu_voice_frequency"
     translation_description="In the menu, to configure the voice frequency, how frequent to announce
       status.