Added setting of osg_SimulationTime and osg_DeltaSimulationTime to the uniforms set by SceneView
Added frame(double simulationTime) and advance(double simulationTime) parameters to
osgViewer::SimpleViewer, Vewer and CompositeViewer.
Updated various examples and Nodes to use SimulationTime where appropriate.
that removeChild(Node*), removeChild(uint) and equivilant Geode methods are
now inline methods, not designed to be overriden, and seperated out the
multiple remove method to be called removeChildren(uint, uint) which is
now the only virtual method. There removeChildren is now the method to
override in subclasses.
This reorganisation requires some call code to be rename removeChild usage
to removeChildren.
