Updated the sample app's "ViewController.swift" file to update the "m…

[ChopinDavid]

…onthLabel" when the user clicks "next" or "previous". It appears that "didScrollToDateSegmentWith" alone, and not "willScrollToDateSegmentWith" is called when we use JTACMonthView.scrollToSegment. So I moved the code that updates the monthLabel text within didScrollToDateSegmentWith instead of willScrollToDateSegmentWith.