* birthday: translation tweaks. (Birthday-Admin.french.php, Birthday-Mails.french.php)

+ calendar: Added my own national day. Because. (Subs-Calendar.php, CalendarHolidays.language.php)

- calendar: removed showbdays setting (I don't think it's being used?), and years 2008-2011. Let's not live too much in the past... (plugin-info.xml)

Signed-off-by: Nao <nao@wedge>