Trace more Kalman filter status in PSAS test.
Quaternions are pointwise applicative functors.
Inhibit unobservable state updates unless moving.
Paul's Kalman filter was non-standard; generalize.

During the Kalman prediction step, Paul Riseborough's filter included
special handling to fold the current accelerometer and gyro measurements
into the process model. By augmenting the state vector with these
disturbances, and the prior covariance matrix with the disturbance
covariance, we can get the same result while using the general form of
the Kalman filter as given in textbooks or Wikipedia.

I suspect this is a standard technique, or at least Kalman filter
folklore, but I haven't been able to find a reference for it.

Note that I forgot to include process noise in previous commits. This
commit makes that explicit and gives me a place to add process noise
later.
Include process noise in Kalman filter.
Inhibit unobservable process noise unless moving.
Don't reference partial CSE map once the next one is created.

This fixes a major space leak in my CSE implementation that was due to
excessive laziness.