Description:
------------
Could you make 2 new combined operators:

`$a ?= 4` => `$a = $a ?: 4`
AND
`$a ??= 4` => `$a = $a ?? 4`

Test script:
---------------
<?php

function ofstr($a = NULL, $b = NULL)
{
   $a ?= 1;
   $b ?= 100;
   return "$a of $b";
}

print_r(
   array(
      ofstr(2, 5),
      ofstr(60),
      ofstr(FALSE, 5)
   )
);

Expected result:
----------------
Array
(
    [0] => 2 of 5
    [1] => 60 of 100
    [2] => 1 of 5
)