Dates before 10/15/1582 are potentially wrong?

[idelem]

Hi,
I'm not sure if this is worth a fix, but think it might be helpful to let you know that by Gregorian calendar, there are supposedly 9 days skipped between 10/4 and 10/15, 1582. (reference here) So the dates before that period might need to be handled differently.
I guess it doesn't really matter given the app's purpose, so just FYI. Apart from that, it's a really cool project.