Fix points_to_spheres bug in 3D

[heinsimon]

Closes #917

[ma-sadeghi]

Thanks for the PR. Could you please also add a unit test to test 2D vs. 3D behaviour?

[heinsimon]

I added a simple test case for 2D and 3D.

I did not add anything for im being a boolean array, since I do not really know what the expected output would be. It feels broken, but I do not know for sure.

[ma-sadeghi]

I added a simple test case for 2D and 3D.

I did not add anything for im being a boolean array, since I do not really know what the expected output would be. It feels broken, but I do not know for sure.

That seems strange, I can't look at it right now, but will do later this week.

[heinsimon]

Is this PR still considered or is it outdated now?

[ma-sadeghi]

Sorry for the delay. I still didn't get the chance to review it. Will do this week hopefully.

[jgostick]

I'm so sorry how long this is taking. Amin has a new job now, so it's all on me at the moment. I think the PR is pretty much ready, I'll just go in and fix the tests myself asap.

[jgostick]

I see that "maintainers are allowed to edit this pull request" is enabled, but I honestly don't know how. I would have expected to see this as a branch on my remote which I could pull locally to work on, but that is not how it works. Soooo, I'm just going to merge it into dev, then create a new PR to fix the tests.