Removed all the plugins BUILD_OSG_* options as these just get in the way of  browsing standard CMake options.
Removed all the plugins BUILD_OSG_* options as these just get in the way of 
browsing standard CMake options.


marchelbling/osg,tomasthoresen/osg,tomasthoresen/osg,tomasthoresen/osg,jtorresfabra/osg,marchelbling/osg,artoolkit/osg,scrawl/osg,artoolkit/osg,marchelbling/osg,scrawl/osg,jtorresfabra/osg,marchelbling/osg,openscenegraph/osg,jtorresfabra/osg,artoolkit/osg,openscenegraph/osg,jtorresfabra/osg,openscenegraph/osg,tomasthoresen/osg,scrawl/osg,openscenegraph/osg,scrawl/osg,artoolkit/osg