== DETAILS
Well, after a lot of code analysis, this seems like the
best way to handle things on the Wii U without also completely
re-architecting the I/O handling in RetroArch.
How it works:
- the top-level wiiu_joypad driver is now nothing more than a
delegator.
- the wiiu-specific drivers live in `wiiu/input/`
- wpad_driver.c handles the WiiU gamepad
- kpad_driver.c handles the wiimotes
- hidpad_driver.c will handle HID devices like the GC adapter, DS3/DS4, etc.
(I say "will" because this isn't implemented yet)
== TESTING
Haven't actually tried the build to see if it works, but it does
compile.
