thin-itx-case

power button: make it 17.5mm to match M16 diameter by freecad.

increase the size of bottom standoff nut pockets to make it easier to handle

power button: make it 17mm. 16 is correct but should have used a hole but I do not want to reslice.

spreadsheet: cleanup, typos, add height

recess connectors a bit and fix standoff pockets depth