tweak caption strings for frames to be start/end

rather than above/below seeing as the caption is entered into the frame
(rather than outside the frame) at either the start or end of the frame
contents

Change-Id: I633ab6a03e9d47aab72cbade1cd812c8aa6c5a94

sw/source/ui/app/app.src

@@ -242,11 +242,11 @@ String SW_STR_NONE
 
 String STR_CAPTION_BEGINNING
 {
-    Text [ en-US ] = "Above" ;
+    Text [ en-US ] = "Start" ;
 };
 String STR_CAPTION_END
 {
-    Text [ en-US ] = "Below" ;
+    Text [ en-US ] = "End" ;
 };
 String STR_CAPTION_ABOVE
 {