This test makes sure OpenGL and CUDA are successfully interoperable. If they 
are, there will be 4 output files representing different surface properties
of an OpenGL rendered star.  scalar_gl.h5 and velocity_gl.h5 are the OpenGL
renderings.  If successful, scalar will be (T, g, null, mu) with maximums
of (29000, 4.1, 0, 1.0).  velocity will be (v_x, v_y, v_z, v_rad). v_z and v_rad
should be equal at ~100.  scalar_cuda.h5 and velocity_cuda.h5 are the same
renderings passed through a CUDA kernel that adds a constant value of 5000.0f 
to each array element.