Count items in database as much as possible (#344)

* Count items in database as much as possible

* Fix the tests

* Remove two useless queries

* Run pragma directive before each sqlite connection

* Pragma for tests too

* Remove debug messages

src/routes/notifications.rs

@@ -13,7 +13,7 @@ pub fn notifications(conn: DbConn, user: User, page: Option<Page>, intl: I18n) -
         &(&*conn, &intl.catalog, Some(user.clone())),
         Notification::page_for_user(&*conn, &user, page.limits()),
         page.0,
-        Page::total(Notification::find_for_user(&*conn, &user).len() as i32)
+        Page::total(Notification::count_for_user(&*conn, &user) as i32)
     ))
 }