do not crash if marblewidget is not used within marble
do not crash if marblewidget is not used within marble

svn path=/trunk/KDE/kdeedu/marble/; revision=994028

David-Gil/marble-dev,adraghici/marble,rku/marble,AndreiDuma/marble,AndreiDuma/marble,utkuaydin/marble,AndreiDuma/marble,tzapzoor/marble,utkuaydin/marble,tucnak/marble,tucnak/marble,adraghici/marble,rku/marble,adraghici/marble,probonopd/marble,rku/marble,probonopd/marble,tucnak/marble,tzapzoor/marble,quannt24/marble,rku/marble,tzapzoor/marble,David-Gil/marble-dev,quannt24/marble,tzapzoor/marble,tucnak/marble,Earthwings/marble,tucnak/marble,oberluz/marble,David-Gil/marble-dev,David-Gil/marble-dev,adraghici/marble,probonopd/marble,quannt24/marble,quannt24/marble,Earthwings/marble,oberluz/marble,AndreiDuma/marble,Earthwings/marble,utkuaydin/marble,adraghici/marble,rku/marble,quannt24/marble,AndreiDuma/marble,oberluz/marble,oberluz/marble,oberluz/marble,David-Gil/marble-dev,probonopd/marble,tzapzoor/marble,probonopd/marble,oberluz/marble,quannt24/marble,rku/marble,tzapzoor/marble,quannt24/marble,Earthwings/marble,Earthwings/marble,tucnak/marble,probonopd/marble,probonopd/marble,utkuaydin/marble,tucnak/marble,utkuaydin/marble,Earthwings/marble,utkuaydin/marble,tzapzoor/marble,adraghici/marble,AndreiDuma/marble,tzapzoor/marble,David-Gil/marble-dev