Vertical Text - Spiff at a 45 degree angle

Extruding at 45 degrees means your polygons can be printed on a vertical face. Use linear_extrude_45 the same way as linear_extrude in your OpenSCAD code.

There are two modes: standalone extrusion, or shallow. Shallow mode is meant to be added or subtracted from a vertical face.

I've added an implementation for Spiff so you can have vertical text.