Update BusinessdayCalendarExcludingTARGETHolidays.java

Fix to include Labour Day as a holiday in the TARGET calender.
(Source: http://www.ecb.europa.eu/press/pr/date/2000/html/pr001214_4.en.html
and http://www.vdb.de/target-arbeitstage.aspx)
Merge pull request #3 from mquirin/master

Update BusinessdayCalendarExcludingTARGETHolidays.java