Fixed particle update bug where a ParticleSystem wouldn't start when loaded during the frame loop due to the _last_frame value not being set.
Fixed particle update bug where a ParticleSystem wouldn't start when loaded during the frame loop due to the _last_frame value not being set.

openscenegraph/osg,openscenegraph/osg,openscenegraph/osg,openscenegraph/osg,scrawl/osg,scrawl/osg,scrawl/osg,scrawl/osg