Updated the List Activity Context Menu to use xml

closes #64

Signed-off-by: Ricky Barrette <rickbarrette@gmail.com>

LocationRinger/res/menu/ringer_list_context_menu.xml

@@ -0,0 +1,9 @@
+<?xml version="1.0" encoding="utf-8"?>
+<menu xmlns:android="http://schemas.android.com/apk/res/android" >
+
+    <item
+        android:id="@+id/delete"
+        android:icon="@android:drawable/ic_menu_delete"
+        android:title="@string/delete"/>
+
+</menu>