From Stephan Huber, added reset of _currentContext when graphics context is closed.
From Stephan Huber, added reset of _currentContext when graphics context is closed.


jtorresfabra/osg,tomasthoresen/osg,openscenegraph/osg,openscenegraph/osg,scrawl/osg,tomasthoresen/osg,scrawl/osg,artoolkit/osg,openscenegraph/osg,openscenegraph/osg,marchelbling/osg,marchelbling/osg,artoolkit/osg,jtorresfabra/osg,scrawl/osg,artoolkit/osg,jtorresfabra/osg,tomasthoresen/osg,tomasthoresen/osg,scrawl/osg,artoolkit/osg,marchelbling/osg,marchelbling/osg,jtorresfabra/osg