Add new methods in the DateFormatter class to defines the list of week day
names and month names.

In the next version of the Flash Player 10.1 we can use the new
globalization API to create a good DateFormatter class with i18n inside.

For the moment i add 4 new methods in the DateFormatter class to defines
the list of month and week day names :

 * getMonthNames( names:Array )
 * getWeekdayNames( names:Array )
 * setMonthNames( names:Array )
 * setWeekdayNames( names:Array )