total_page_no added to api/transactions

issue: https://github.com/moneroexamples/onion-monero-blockchain-explorer/issues/55#issuecomment-299680916

src/page.h

@@ -4289,6 +4289,8 @@ namespace xmreg
             j_data["page"]           = page;
             j_data["limit"]          = limit;
             j_data["current_height"] = height;
+            j_data["total_page_no"]  = (height / limit);
+
 
             j_response["status"] = "success";