single 7mm push button box

changes from the original file are:
- squared off the box
- changed it to one button hole
- increased box height by 10mm to make room for wiring
- created a back lid which snaps on, with a 9mm hole for a 3/8" rubber blanking grommet

the switch i'm using is not waterproof so sealing the box is kind of silly but i did it anyways. this is for a horn on a boat. i plan to slit the grommet and pass my wiring thru.