- move a few variables from SceneDrawer to FRenderViewpoint.
The global r_viewpoint variable is left alone now to always represent the current viewpoint to the play code.
The main reason behind this change is to reduce the amount of global variables being used by the hardware renderer's scene processing code.
I missed this part when repurposing the vboindex members to store the index buffer offsets.
However, since both indices are needed, they need another set of variables.
