Avoid losing previous values on static variables

If we initialize each time the variable, we lose previous changes, so for example cache variables are retrieved every call.

This patch tries to solve it.

Here is also a quick php test for structured and OO ;-)

function load() {
    return array(1,2,3);
}

class a {
    private static $cache;
    public function get() {
        if (!isset(self::$cache)) {
            echo "cache __NOT__ set";
            self::$cache = load();
        }
        else {
            echo "cache set";
        }
        return self::$cache;
    }
}

$obj = new a();
$arr = $obj->get();
$arr = $obj->get();
var_dump($arr);

echo "<hr>";

function sget() {
    // without refering the variable with static again it's considered a new variable, not our static one
    static $scache;
    if (!isset($scache)) {
        echo "cache __NOT__ set";
        $scache = load();
    }
    else {
        echo "cache set";
    }
    return $scache;
}

$arr2 = sget();
$arr2 = sget();
var_dump($arr2);

Also, already applied to my master branch if you want to pull :-D