Added GLES3 path for setting up with EGL
Added GLES3 path for setting up with EGL

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