use the key server preference to fill a Spinner in the key server query activity, allowing to query each server, also moved some previously static labels into strings.xml

Update issue 9
Key server preferences are now used in key server query activity.

res/layout/key_server_query_layout.xml

@@ -20,6 +20,11 @@
     android:layout_height="fill_parent"
     android:orientation="vertical">
 
+    <Spinner
+        android:id="@+id/keyServer"
+        android:layout_width="fill_parent"
+        android:layout_height="wrap_content"/>
+
     <LinearLayout
         android:layout_width="fill_parent"
         android:layout_height="wrap_content"