Removed State::AppliedProgramObjectSet container and Obsever usage from osg::State to address threading bug crash.

The State::AppliedProgramObjectSet wasn't ever being used actively in the current rev of the OSG so populating and clearing was no longer neccessary, allowing the code to be removed completely.


git-svn-id: http://svn.openscenegraph.org/osg/OpenSceneGraph/trunk@14377 16af8721-9629-0410-8352-f15c8da7e697