Description:
------------
Object that do not implement __toString, now stop the script with "PHP Catchable fatal error:  Object of class {className} could not be converted to string in ..."

But for backward compatibility, if __toString is not  implemented, it should return the old object id value, or the name of class of the object for example.

I agree that nobody can rely on old ObjectId string, but there?s thousand scripts that stringfy data for logging,
like this:

function log($vars)
{
foreach($vars as $var) echo $var;
}

function test($a, $b)
{
    log(func_get_args());
}

Reproduce code:
---------------
class Foo { }
echo new Foo;

Expected result:
----------------
Old behavior of conversion from object to string

Actual result:
--------------
Catchable fatal error: Object of class Foo could not be converted to string in ...