fixed BUG reported by Jens Teubner from Konstanz:
fixed BUG reported by Jens Teubner from Konstanz:

ifthenelse didn't take proper care when returning BATs

zyzyis/monetdb,zyzyis/monetdb,zyzyis/monetdb,zyzyis/monetdb,zyzyis/monetdb,zyzyis/monetdb,zyzyis/monetdb,zyzyis/monetdb,zyzyis/monetdb,zyzyis/monetdb