Description:
------------
Simplexmlelement->node auto-typecasts right to int or string but a typecast to bool does the same thing as is_set().
to check if a node contains a true or a false value you have to check 
(bool)(string)$simplexmlelement->node.


Reproduce code:
---------------
<?php
$xmlstring="
<xml>
<node>0</node>
</xml>";
$xmlelement=new SimpleXMLElement($xmlstring);
echo "(int)element: ";
var_dump((int)$xmlelement->node);
echo "--\n";
echo "(bool)element: ";
var_dump((bool)$xmlelement->node);
echo "--\n";
echo "(bool)(string)element: ";
var_dump((bool)(string)$xmlelement->node);

Expected result:
----------------
(int)element: int(0)
--
(bool)element: bool(false)
--
(bool)(string)element: bool(false)


Actual result:
--------------
(int)element: int(0)
--
(bool)element: bool(true)
--
(bool)(string)element: bool(false)