Fixed downloads for multiple days (-d/--days option)

I just found your fork today. I was using the original kirbyt version, and it broke today due to changes in iTunesConnect.  But your fork works great, so thanks!

I did notice it was only downloading the first day's reports, even though I was using "-d 7" to download 7 days, so I fixed that bug. Please feel free to pull the fix back to your fork.

Thanks again
Mike