mirror3dFunction in std::transform

Create a mirror image of a 3D solid/surface/body, across some specified mirror axis.

Name	Type	Description	Required
`bodies`	[`Solid`; 1+]	The body or bodies to be reflected.	Yes
`across`	`Edge` or `Plane` or `Axis3d` or `Segment`	The axis (or other geometry) to reflect across.	Yes