Comment 13 for bug 3528

I thought about this and I think that returning integers is saner than returning strings. The day of the month IS a number, actually, so why not treat it as such? If you want advanced number formatting you should use sprintf() and friends. And since the module will also feature functions to convert a date to YYYY-MM-DD format (for which the zero padded month and day numbers are required), I think a zero padded string is not needed at all.