Clean up worldedit.spiral about minetest-worldedit HOT 2 CLOSED

/help /spiral
  //spiral : Add spiral at WorldEdit position 1 with width , height , space between walls , composed of

The spiral makes square turns counterclockwise on the Y plane, starting going South, ending going either North or South.
The corner of the spiral is placed one wall away from P1. To expand it would require deleting it first, because of it not being centered.
<width> is the diameter measured in walls (in the direction perpendicular to the direction the ends are moving).
The height of the walls is h = <height> + 1; h = (h >= 2 and h or 2)
The space between walls is <space> - 2. So if you wanted two nodes of space between walls, you would use 4. <space> measures the distance between the outside sides of the walls.
The very center of the spiral goes one more node than the space between the walls. Instead of being 1x1, 2x2, or 3x3, it would be 2x1, 3x2, or 4x3.
The outside end stops <space> nodes before being in the same line as the perpendicular wall.

It would be better to rewrite this than to modify it.

from minetest-worldedit.

WorldEdit's spiral functionality has been completely rewritten a while ago back in version 1.0, or somewhere around that time. As a result, this is now done!

from minetest-worldedit.