Roadmap to better support partials on manifolds

1. AMP 41 will implement Mahony's method, but won't support generic Riemannian and need coordinate workaround for partials (see below)
2. Partials fall back to product manifold (i.e. TR on SE(n)) coordinates
3. Handle "coupled" partials such as yaw on SO(3) on a case-by-case basis, numerical solutions have starting point
4. In parallel start generic semidefinite solution.
