Externals: update libusb to version 1.0.19
Externals: add Dolphin-specific patches to libusb
Externals: add hidapi 0.8.0-rc1
Externals: steal & modify hidapi.vcxproj from Armada
WiimoteReal: reimplement using HIDAPI

Using the HIDAPI library has the advantage that we get Wiimote and
DolphinBar support on all platforms with only one IO implementation.