[fluxus] fixes

[Dave Griffiths]

> i just updated and this does not fix my crash

do nurbs primitives work now? maybe it's nothing to do with the texturing
problem then.

the plane prim is built in libfluxus/src/GraphicsUtils.cpp line 78, and
the primitive is created in src/FluxusBinding.cpp line 107. I can't see
anything obviously wrong here - it creates two coincident quads each
facing in opposite directions. it's pretty much the same deal as the cube
(and other polyprims) otherwise. have a play with it - try commenting out
the last quad?

cheers,

dave