OpenSCAD Attachable Thread Library (BOSL compatible)

This OpenSCAD library creates threaded objects using Adrian Schlatter's (and others) wonderful thread library for OpenSCAD - see [here](https://github.com/adrianschlatter/threadlib). Threadlib makes it incredibly easy to create real world thread objects for a wide range of standard threads.

My library creates *attachable* threadlib objects which are compatible with the BOSL library - [more info on BOSL here](https://github.com/BelfrySCAD/BOSL2) - so the thread objects have anchors which attach to any other BOSL attachable object. You can see the anchors in the image above. If you're new to BOSL, you can learn about its attachment methods in this [tutorial](https://github.com/BelfrySCAD/BOSL2/wiki/Tutorial-Attachments). Anchors and attachments allow you to easily build complex assemblies without the cumbersome translate() statements that many OpenSCAD programmers will be familiar with. BOSL actually provides many more useful features besides attachments.

The BOSL library has its own s