As @Levi-Armstrong and @Jmeyer1292 just pointed out in their presentation at ROSCon, there is a nonsensical performance bottleneck in MoveIt at the moment because we use Affine3d (wrongly?).

Specifically, I just verified that calling Affine3d::rotation() const actually computes SVD in the background.

We clearly want to change this.

Levi argued for Eigen::Isometry3d instead of Eigen::Affine3d. I agree that this makes sense in melodic.
Because we want to keep kinetic api stable though, can we get rid of rotation() in favor of linear() throughout the code base?