More minimal wallet

Several tweaks to harperwilliame's excellent design, this is my new favorite wallet, much smaller than other mini printable wallets that I've come across before, and as usable.

Room for about 8 cards (credit, gift, license...) and/or folded cash, easily flicked out with your thumb.

The TPU version is probably best with a semi-flex filament (I used Priline which is shore hardness of 98a, pretty hard but still flexible and great for this - I like that it still covers the cards.)

I've printed the PLA/PETG version with both filament types and they work well, but probably PETG will hold up longer.

No supports needed, any layer height (I used .25), 100% infill or multiple walls should do it.

[Update 7/25/2020: I've added a modified PLA/PETG/Nylon version that should be a bit sturdier, it prints great in nylon filament, though my favorite is still TPU.]

[Update 1/2021: have added a version of the TPU wallet with a semi-expanding pocket for cash, business cards, etc. Must be