Description:
------------
I think it's better, if the implode() function call the __toString() method of a array width objects.

Reproduce code:
---------------
class obj{
  function __construct($name){
    $this->name = $name;
  }
  function __toString(){
    return $this->name;
  }
}

$arry = array();
$arry[] = new obj('first');
$arry[] = new obj('second');
$arry[] = new obj('onemore');

echo implode(', ', $arry);

Expected result:
----------------
first, second, onemore

Actual result:
--------------
Object, Object, Object