tracklib: OpenSCAD library for rendering toy train parts

A parametric library of modules for creating parts compatible with toy trains (currently focused primarily on Thomas- and Brio-compatible wooden trains, as well as Thomas Trackmaster (motorized plastic) and Take-N-Play (die cast).
 
Some functions in this library require other [dotscad](https://github.com/dotscad/) files. I would recommend cloning that repository into the same parent directory that contains this repository.
 
This OpenSCAD library is part of the [dotscad](https://gi