Customizable Ultimate Drawer System Shelf

# Ultimate Drawer System
Intended to be the ultimate drawer system that is
* printable with FDM printing
* optimizable for anything you store in drawers
* compatible with Thingiverse's Customizer
* backwards-compatible with MarcElbichon's Ultimate Drawer System
* written for ease of improvement (which could use some improvement)

This Thing is the shelf customizer. For the drawer customizer, see [Customizable Ultimate Drawer System Drawer](https://www.thingiverse.com/thing:3796197). For drawer inserts/dividers see [Customizable Ultimate Drawer System Inserts](https://www.thingiverse.com/thing:3798783). For the foot, see [Ultimate Storage Drawer System Feet](https://www.thingiverse.com/thing:3815722)

## The System
* Drawers and complementary shelving units are sized in units called "Us".
* If only one dimension is given, it is assumed to be the height and the width and depth are assumed to be 1U.
* A 1U drawer is 120 mm wide by 120 mm deep by 19 mm high.
* A 2U drawer is