libusb-win32 driver support

[emoose]

Instead of WinUSB there's also the libusb driver that can be installed for a device, libwdi can install this driver fine, and Xb2XInput seems to recognise devices that use that driver... but then after connecting to it immediately decides to disconnect. I guess non-driver libusb must be returning an error code somewhere after opening the device.

Not a huge problem since we suggest/automate installing WinUSB anyway, but supporting libusb drivers would still be a nice addition.

[emoose]

Solved it, we weren't getting disconnected from libusb, it was actually making a new connection to the same device over and over, seems libusb allows that while WinUSB gives an error code instead

I can't find a good way to check if we're already connected to a device though (libusb_claim_interface doesn't seem to work...), so instead we store the USB port #s of each connected controller, and then when we try connecting a new controller we check the USB port # of the new controller against our connected ones, seems to work fine this way, I wish there was an easier way to do it though...