that they arn't created on the stack inappropriately.
Split the implemention of Matrix up so that it is a simple no referenced counted
class and can be safefly created on the stack. To support referenced counting a
seperate subclass now exists, this is RefMatrix which inherits from both Matrix and
Object.
Renamed the osg::VisualsSettings to osg::DisplaySettings, and
osgUtil::VisualsRequirementsVisitor to osgUtil::DisplayRequirementsVisitor.
Added support for OSG_SCREEN_HEIGHT into osg::DisplaySettings, and added
a DisplaySettings* to the constructors of osg::SceneView and osg::Camera.