Light & Motion Seca to GoPro adapter

Adapter to attach a Light & Motion Seca light on a standard GoPro mount. Based on thrasher's Taz-to-GoPro mount from https://www.printables.com/model/77679-light-motion-taz-gopro-adapter . I expanded the outer barrel, hollowed out a cavity to fit the Seca's pivot post (including the small black endpiece that normally sits within the factory Seca mount), and counter-sunk the screw head at the bottom. If you don't want to counter-sink (e.g. if you want to use a washer to distribute the clamping stress), simply set that variable to false in the OpenSCAD source. If fabricating this in PA11, I think it's sturdy enough to handle the stress without a washer but YMMV. Note that this adapter will require a slightly longer M3 screw than the 10mm version included with the factory Seca mount, I recommend 12-15 mm. STL file is scaled at 1 unit = 1 mm resolution.