UPC-A Barcode Generator

Customization Instructions:

1. Install OpenSCAD
2. Download latest version from https://github.com/X-Illuminati/glyphinator
3. Copy upc-example.scad
4. More API details in barcodes/upc.scad

Dualstruders:
Create one model with parameters bar=1, space=0 and a second model with bar=0, space=1 (and/or quiet_zone=1).