Parametric Toilet Seat/Lid Hinge

Remix of toilet seat hinge [http://www.thingiverse.com/thing:39750](http://www.thingiverse.com/thing:39750), with the **added** ability to create *either* a lid hinge or a seat hinge.

To customize, use OpenSCAD or the Customizer app. For a hinge which attaches to the seat, choose a `sidedness` of 0; for a hinge which attaches to the lid, choose a `sidedness` of 1. The `sidedness` variable affects whether the screw head cutouts are placed on the same side as the hinge or the opposite side of t