Add strings for next/prev page and message html (Goes between the <a...> and </a>)

web/lib/msgsconfig.ssjs

@@ -2,3 +2,7 @@ max_groups=10;
 max_subs=10;
 max_messages=10;
 max_pages=10;
+next_msg_html="Next Message";
+prev_msg_html="Previous Message";
+next_page_html="NEXT";
+prev_page_html="PREV";

web/lib/msgslib.ssjs

@@ -89,7 +89,7 @@ function find_np_message(offset,next)
 			return(last_offset);
 		if((idx=msgbase.get_msg_index(true,last_offset))==null || idx.to!=user.number)
 			continue;
-		return(last_offset);
+		return(hdr.number);
 	}
 	return(undefined);
 }