Refactored/ streamlined UserSession code

Makes it easier to tell when a user is signed in

dev_mvc/controller/Database.php

@@ -235,7 +235,6 @@ Class Database{
         $query->execute();
         //Check hoeveelheid teruggestuurde rijen
         if($query->rowCount() == 1){
-            echo('session valid in db<br>');
             return true;
         }
         else{
@@ -243,7 +242,6 @@ Class Database{
         }
     }
     static function invalidateSession($token){
-        echo("hek");
         //Init db connection
         $con = Database::connectToDB();
         //Bereid query voor