nrf52 pca10040 case

Famousjasper made a nice case for the Nordic nRF52 development board (pca10056 variant). But we have a bunch of pca10040 boards kicking around, so I shortened it, removed a mounting peg and moved the reset button.

The rest of the parts aren't different from Famoujasper's.

Note: The case parts all seem to work fine with HIPS, except the screws. There's abit too much overhang to print without extra effort. But PLA should work just fine.