Use the *express* native rolling instead (#1245)

* Alternative is "Remember me" option although I think I'd rather have a "Forget me" option by default.

Post #1202 and related to #604

Auto-merge

app.js

@@ -294,6 +294,7 @@ app.use(session({
   cookie: {
     maxAge: 4 * 60 * 60 * 1000 // 4 hours in ms
   },
+  rolling: true,
   secret: sessionSecret,
   store: sessionStore
 }));
@@ -306,14 +307,6 @@ app.use(function (aReq, aRes, aNext) {
 });
 app.use(modifySessions.init(sessionStore));
 
-// Rolling user session
-app.use(function (aReq, aRes, aNext) {
-  if (aReq.session.user) {
-    aReq.session.user._touched = new Date();
-  }
-  aNext();
-});
-
 app.use(favicon(__dirname + '/public/images/favicon.ico'));
 
 // Set up the views