Tank track links - 2.5x wider

A horizontally scaled variant of @mscourch's tank track design.

I've also tweeked the links for using "Tie wire" as rivets, which is ~2mm wide. Added holes in the sides, to tuck the wire nubs into, to keep them from falling out (or stabbing your hand, as tie wire tends to be sharp)

Track:
50mm wide (20mm was default)
~2.8mm hole width (3.3mm was default, I want to go down to 2.3mm but got sick of battling SketchUp to fill it correctly)
Side holes are 2.4mm tall, 1mm wide, 1mm deep

Driver Wheel:
18mm wide (was 6mm). I tried 15mm wide, and it adds some slop/play, which im not sure is desireable or not yet. The 18mm fits with about 1mm clearence on each side.

I've successfully printed the first one. The first things I want to change, is to double the size and depth of the pin retention holes.