Parametric NATO rail (picatinny compatiable)

**This is an old version**

**A never version is here:**

https://www.thingiverse.com/thing:6384306

This file defines a module that creates a NATO accessory rail on the xy plane, running up the y axis from the origin, with the top in the z-direction. The dimensions of this rail are as in standardization agreement 4694 (but of course results will depend on your printer).

This style of rail is backwards-compatible with picatinny rails - and for most intents and purposes may as well *be*