Added FallbackValue in XAML for Calendar control styles:
Added FallbackValue in XAML for Calendar control styles:

MahApps.Styles.CalendarButton
MahApps.Styles.CalendarDayButton
MahApps.Styles.CalendarItem

ye4241/MahApps.Metro,MahApps/MahApps.Metro,batzen/MahApps.Metro