WiimoteEmu: Remove Spy method

This is the only use for a lot of unused methods and structs, and it's a
poorly written mess that doesn't even compile. Just remove it so we can
clean up the rest of a lot of code.
WiimoteHid: Remove unused structs
Nunchuk: Use the accel_cal struct directly in nu_cal
Nunchuk: Hardcode Nunchuk stick calibration values

The game can never change these, so there's no reason to make it
dynamic. Just put the constants in the code.

While we're at it, take the time to clean up the code and also
and document several of the hacks we're doing inside to make the code
clearer to understand.
Nunchuk: Hardcode Nunchuk accelerometre calibration values as well
WiimoteEmu: Hardcode acceleration calibration values

Now we don't have any runtime calibration at all.
Merge pull request #1477 from magcius/nunchuk-cleanup

Nunchuk cleanup