Modify body Jacobian F. Junho has an identity in the db/db term, which is not
consistent with the handling of X and V.

Update covariance based on known estimate (GPS aided)

Dynamically adjusted state size. We can add and delete features as needed.
Junho's code requires a fixed state size.

Treat measurements as independent. Compute S_i individually for each measurement
and compose S as block diagonal for speed improvement.

Use quaternion reflection instead of Householder Transformation for determining
the predicted reflection measurement.

Below here is not yet implemented:

Add initial reflection view.