IDs for generic XInput controllers
Compatible with the Xbox 360 controller, the Xbox One controller, and anything that masquerades as either of those.
NOTES
WINDOWS: we assume the user is using the default drivers that ship with windows.
LINUX: we assume the user is using the xpad driver, specifically Valve's version, steamos-xpad-dkms (we got weird errors when using xboxdrv). For full instructions on installation, see: http://askubuntu.com/questions/165210/how-do-i-get-an-xbox-360-controller-working/441548#441548
MAC: we assume the user is using the 360 Controller driver, specifically this one: https://github.com/360Controller/360Controller/releases