DST issue

[SaraivaDaniel]

I've just encountered an error in datepicker today while working with it here in Brasil. Coincidentally, today is the first day of DST back here. So, when I select day 19/10 in the popup, the textbox displays 18/10 - I've searched around and found that the issue is actually in V8 engine, but I propose a workaround here.

I don't know how to fork and create a pull request, so I'm just posting the fix here based on current master commit 5f26ae7.

On file date.js, add following lines after line 499:

if (Number(s.substr(iD, 2)) - d.getDate() === 1) {
    d.addDays(1);
}

Basically it'll just check the day on the created Date object against the supplied string, and add one day in case it's offset because of DST issue.