Compatibility fix for 2019.4.40f1

[Eideren]

2019.4.40f1doesn't support static local functions, nor inactive optional argument for UnityEngine.Object.FindObjectsOfType.
I'm not sure what helper surfaces are, so not even sure that my change would work in this context - let me know.

Small note, there's a ton of mixed whitespace in files, we may want to do something about that.

[nukeandbeans]

Helper surfaces are the meshes that get used to display debug information in the scene through the dropdown @ the right of the bottom toolbar.

The whitespaces thing is something I've been wanting to fix, but there is a lot of whitespaces to change, and would need a thorough check to make sure they wouldn't break anything (if done with automation, e.g. file > format). It'd have to be a PR of its own.

I tracked down where the local method changes came from, and the changes were from https://github.com/Kerfuffles/realtime-CSG-for-unity/pull/1/files
It seems I disregarded changing them back to older compatibility, but I guess I hadn't checked that version to make sure it worked with it. Thanks for the fixes!