Description:
------------
There are three different ways objects are converted to strings and they are inconsistent (depends on what function you are using). I think all object-to-string conversions should be done via __toString() if it is defined, even if the object is in quotes.

Reproduce code:
---------------
<?php
	class Message {
		function __toString() {
			return "Hello, World!\n";
		}
	}

	$w = new Message;
	echo("$w");
	echo("Message: " . $w);
	echo(substr($w,0));
	echo($w);


Expected result:
----------------
Hello, World!
Message: Hello, World!
Hello, World!
Hello, World!

Actual result:
--------------
Object id #1
Message: Object id #1
Object
Hello, World!