In an effort to learn as much as possible about best development practices and software architecture, I created my own MVC framework using PHP (github: https://github.com/alemmedia/miniMVC).I've found that this has resulted in phenomenal improvements in my programming skills, but I'm still limited by my own limited experience when it comes to reviewing my code.I'd like to get your critique on one of my least favorite classes (I always feel like there is something off about them):Here is my Session singleton I use to access/manage session data.class Session{/** * @var object Holds the single instance of Session */private static $instance;/** * @var string The session id of the current session */protected $id;/** * @var mixed The data to be held in session. */public $data;/** * __construct - Starts session * *  Establishes Session::data reference to $_SESSION superglobal array, and sets session id. *  Privately held an called only by Session::open for singleton functionality */private function __construct(){    session_start();    $this -> id   = session_id();    $this -> data =& $_SESSION;}/** * open - Creates singleton instance of Session object *  * @return object */public static function open() {    if ( !isset(self::$instance) )        self::$instance = new self();    return self::$instance;}/** * set - Recieves variables to set to $_SESSION array * * @param string $property   The property to set to the session * @param mixed  $value      The balue to set to the property * @param bool   $make_array If set to true the property will be an numeric array */public static function set($property, $value = null, $make_array = false){    if ( is_array( $property) ){        foreach($property as $key => $single_property)            Session::open() -> set($key, $single_property);    }else{        if ($make_array == false)            Session::open() -> data[$property] = $value;        else            Session::open() -> data[$property][] = $value;    }}/** * del - Recieves variables to delete in $_SESSION array * * @param string $property   The property to delete from the session */public static function del($property){    if ( is_array( $property) ){        foreach($property as $key => $single_property)            Session::open() -> del($key);    }else        unset(Session::open() -> data[$property]);}/** * get - Returns variables from $_SESSION array. *  * @param string $property   The property to retrieve from the session * @return mixed|bool        The retrieved property or false. */public static function get($property){    if ( isset( Session::open() -> data[$property] ) )        return Session::open() -> data[$property];    else         return false;}/** * get - Returns variables from $_SESSION array and subsequently deletes them. *  * @param string $property   The property to retrieve and delete from the session * @return mixed             The retrieved property. */public static function getThenDel($property){    $result = Session::open() -> get ($property);    Session::open() -> del ($property);    return $result;}}Let me know if you've spotted any mistakes or have any suggestions.Also, if you've found any code in the GitHub repository to be sub-optimal, I'd be happy to hear your comments.
PHP MVC Framework Class
php;mvc