Xiaomi Yi 4K pocket case w/ thick screw retainer

I had a lot of difficulty printing the original by @edba2000 because the "U" part used to retain the camera by the screw thread was very thin and weak. This updated version prints great using [Inland natural PETG](https://www.amazon.com/Inland-1-75mm-Natural-Printer-Filament/dp/B00YT12Q08/ref=as_li_ss_tl?ie=UTF8&qid=1510528365&sr=8-1&keywords=inland+natural+petg&linkCode=sl1&tag=7f2a-20&linkId=cd35cb531093274e5132478cedd76f05) on my [Monoprice Select Mini](https://www.amazon.com/Inland-1-75mm-Na