The motions we feed into the projection map now need to be expressed in
uniform coordinates. I've verified by hand that `tangent_motions_unif`
and `tangent_motions_std` represent the same motions.
Instead of finding the kernel in the standard coordinates and then
expressing it in the projection coordinates, work in the projection
coordinates from the beginning by applying a change of basis to the
input matrix.
In the previous commit, the nudge was written in standard coordinates,
so the example shouldn't have worked. However, by sheer dumb luck, the
standard and uniform coordinates match for this particular nudge. In
fact, the expression used before to get the standard coordinates may
even produce equivalent floating point values as the expression used
here to get the uniform coordinates. That would explain why the example
prints exactly the same output in this commit.
