Xiaomi Yi USB door fix

**A replacement for the back door of Xiaomi Yi.**
I lost this part of the camera within two weeks of owning the Yi cam...
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This is a remix from thing #846082 (http://www.thingiverse.com/thing:846082). I had problems printing the thin walls of the USB and HDMI ports, because they were thinner than my nozzle. So the print ended up with only printing the bottom of the door.
I filled both port boxes with solid material, now it is working fine!