Cable-Driven Tool Changer Zesty Nimble Head (Draft!)

This is a *draft* tool head of a zesty-nimble-based E3D V6 hotend. It's compatible with my [Cable Drive Toolchanger](https://www.thingiverse.com/thing:3365456).

## This is a Work-in-Progress
There are still some TODOs that this head deserves:
* a filament cooling fan
* testing


That said, I'm offering it up in hopes that it is useful to others while I'm building up my printer.


## Credits:
* I used the [Zesty Mockup](https://www.thingiverse.com/thing:1843195) to make this assembly