Description:
------------
Arrays often need to be sorted using a "natural order" algorithm. There are 
currently functions in PHP for sorting single arrays this way (natsort, 
natcasesort), but nothing exists for a multisort.

It would be great to see a SORT_NATURAL option in the array_multisort function.

Test script:
---------------
$a	= array(
	'Second',
	'First',
	'Twentieth',
	'Tenth',
	'Third',
);

$b	= array(
	'2 a',
	'1 b',
	'20 c',
	'10 d',
	'3 e',
);

array_multisort($b, SORT_NATURAL, $a);

var_dump($a, $b);

Expected result:
----------------
array
  0 => string 'First' (length=5)
  1 => string 'Second' (length=6)
  2 => string 'Third' (length=5)
  3 => string 'Tenth' (length=5)
  4 => string 'Twentieth' (length=9)
array
  0 => string '1 b' (length=3)
  1 => string '2 a' (length=3)
  2 => string '3 e' (length=3)
  3 => string '10 d' (length=4)
  4 => string '20 c' (length=4)