Prevent illegal inputs

[vabold]

The TAS community has decided to add arbitrary restrictions to what is considered a valid RKG. Thus, we now need to determine and implement logic to account for them.

If the accelerate and brake flags are not set, the drift flag must not be either. This is to match the hardware controller behavior (of which two have been confirmed and two are speculated).

To avoid Kinoko becoming a subset of the physics engine, run validity in this context will become optional.