add origin marker option to viewer.c
add origin marker option to viewer.c

runewake2/opengl-examples,JohnRThomas/opengl-examples,runewake2/opengl-examples,JohnRThomas/opengl-examples,runewake2/opengl-examples,runewake2/opengl-examples,JohnRThomas/opengl-examples,JohnRThomas/opengl-examples