Description:
------------
If the following example-array was sorted by 'natsort' with PHP-Version 5.2.9-2 and 5.2.10 the resulting sort sequence is different:

Example-Array
    [0] => 1_3
    [1] => 0_0
    [2] => 3_10
    [3] => 3_4
    [4] => 2_13

natsort - Result with PHP-Version 5.2.9-2
Array
    [1] => 0_0
    [0] => 1_3
    [4] => 2_13
    [3] => 3_4
    [2] => 3_10
 
natsort - Result with PHP-Version 5.2.10
Array
    [0] => 1_3
    [4] => 2_13
    [3] => 3_4
    [2] => 3_10
    [1] => 0_0

Reproduce code:
---------------
#once for PHP-Version 5.2.9-2 and once for 5.2.10
$a = array('1_3','0_0'.'3_10','3_4','2_13');
natsort($a);
print_r($a);

Expected result:
----------------
sort sequence should be the same between both (all:-) versions