Fixed crash associated with .osg files which contain empty description fields.
From Sondra Inverson, added support to .ive plugin for osgSim::DOFTransform.
osgSim::LightPointNode, the max pixel size from was originally in osg::LightPoint.
Added additional get/set methods to osg::LightPointNode.
Increased the compute pixel size by a ratio 1.41 (sqrtf(2)) to correlate the
computed size with the actual size seen on screen.
