Monday as first day of week for german language

quick "default" setting fix. Should be a user setting independend from users prefered language setting.

First day of the week. "0" means display Sunday first (mostly America, India, Japan)
"1" means display Monday first (ISO 8601, all of Europe, many asia countries)
 "2" Saturday first (arab countries)

https://upload.wikimedia.org/wikipedia/commons/e/e2/First_Day_of_Week_World_Map.svg

js/jscalendar/lang/calendar-de.js

@@ -43,6 +43,9 @@ Calendar._SDN = new Array
  "Sa",
  "So");
 
+// First day of the week. 0 means Sunday, 1 means Monday
+Calendar._FD = 1;
+
 // full month names
 Calendar._MN = new Array
 ("Januar",