suzerain: #2998 draft 2point API

Local-only portion of computations as I will roll up the
Allreduce later.

git-svn-id: https://svn.ices.utexas.edu/repos/pecos/suzerain/trunk@44574 0bd85f0b-c151-43b9-a1e9-27231104551f
suzerain: #2998 draft zlocal

git-svn-id: https://svn.ices.utexas.edu/repos/pecos/suzerain/trunk@44575 0bd85f0b-c151-43b9-a1e9-27231104551f
suzerain: #2998 fix conjugate symmmetry

git-svn-id: https://svn.ices.utexas.edu/repos/pecos/suzerain/trunk@44576 0bd85f0b-c151-43b9-a1e9-27231104551f
suzerain: draft 2-point xlocal

git-svn-id: https://svn.ices.utexas.edu/repos/pecos/suzerain/trunk@44577 0bd85f0b-c151-43b9-a1e9-27231104551f
suzerain: #2998 use Eigen Matrix/Vector API

The logic is a bit more explicit and less prone to error
when written using the Eigen Matrix API.  That's because
adding a Scalar to a VectorXc is verbotten.

git-svn-id: https://svn.ices.utexas.edu/repos/pecos/suzerain/trunk@44578 0bd85f0b-c151-43b9-a1e9-27231104551f
suzerain: #2998 draft twopoint_{x,z} API

git-svn-id: https://svn.ices.utexas.edu/repos/pecos/suzerain/trunk@44579 0bd85f0b-c151-43b9-a1e9-27231104551f
suzerain: draft twopoint_x impl

git-svn-id: https://svn.ices.utexas.edu/repos/pecos/suzerain/trunk@44580 0bd85f0b-c151-43b9-a1e9-27231104551f
suzerain: #2998 draft twopoint_z

git-svn-id: https://svn.ices.utexas.edu/repos/pecos/suzerain/trunk@44581 0bd85f0b-c151-43b9-a1e9-27231104551f