Make DS4 passthrough conditional

[dogtopus]

Currently DS4 passthrough overrides the signals generated by the main controller unconditionally, which breaks e.g. TP+A and prevents the main controller to send button presses, etc. that are overridden by the DS4. It would make more sense to only override signals when there are real actions on the DS4 end.

Possible approach:

• For buttons, override when there is a press or a release.
• For analog sticks and triggers, override when the value is located outside of the deadzone.
• For touchpad, override when there are any touches.
• (Future) For gyro, accel, etc., override when the difference of value exceeds certain threshold.