How do I get the multimedia keys on my keyboard to do anything? I have a Sierra mac with a MS Natural Key 4000 keyboard.  It's got a bunch of special keys that I'd like to do stuff with.  Out of the box, only volume up/down/mute and play/pause work do anything.

I tried using BeardedSpice to bind these keys.  It didn't respond when I hit them.  Karabiner-EventView wasn't any better - I could see other keys being typed, but these ones didn't trigger anything.
Got it!  USB overdrive heard the keys and let me map them to arbitrary osascript.  http://www.usboverdrive.com/USBOverdrive/News.html