Description:
------------
Subtracting a month using strtotime does not always subtract a month.

Reproduce code:
---------------
<?php
print date('Y-m-d', strtotime('-1 month'));
?>


Expected result:
----------------
Assuming the code is run on 2006-03-29, I would expect the result to be 2006-02-28, which is one month ago.

Actual result:
--------------
2006-03-01

This is not one month ago. This has been reported as a bug before but marked as "Bogus" - no idea how not subtracting one month from a date correctly is bogus... and I wasn't allowed to add this to the notes system in the manual to warn others about this odd behaviour., so here it is again as a bug report.