Duet Wifi housing

I really liked the original by pcsentinel but decided to make a few modifications to fit my needs.

Overall the design was brilliant so my modifications included:
- adding cable tie slots at the entrances and in a few other places to hold the cables
- adding a case front that allows the USB connector to be used and the SD card to be accessed
- slightly resizing the box
- adding lugs to locate the small box against the larger one
- changing the lid hold down screw arrangement to suit the e