Zero transmission on oversized apertures

[h-greer]

For many of the dynamic aperture classes (I've tried CircularAperture and SquareAperture, but it probably affects others), creating a clear aperture bigger than the wavefront causes the aperture to drop to zero transmission. MWE below (run on latest dLux off PyPI but I don't think this part of the code has been changed since then).

npix = 512
diam = 2.4
coords = dlu.pixel_coords(npix, diam)

small_circle = dl.CircularAperture(diam/2)
large_circle = dl.CircularAperture(diam)

print(small_circle.transmission(coords, diam/npix).sum()) # > 0. as expected
print(large_circle.transmission(coords, diam/npix).sum()) # = 0. which is incorrect

This sounds like an outrageous edge case but it does come up modelling oversized components. I'm not quite sure where the problem is, but I'm happy to diagnose it myself when I get a chance. I don't imagine this is going to affect most dLux users.