v1.1.0

• ENH: reduce_ghosts supports halos wider than a rank's interior (and ranks
  without grid points) by relaying through intermediate ranks; it is now the
  exact adjoint of communicate_ghosts for any decomposition
• ENH: The FFT engine's field helpers (real_space_field,
  fourier_space_field and their register_* variants) accept sub_pt
• BUG: FFT of fields with multiple sub-points returned garbage (issue #192);
  fft/ifft now reject pairs with differing component or sub-point counts
• BUG: communicate_ghosts/reduce_ghosts reject fields from a foreign field
  collection, e.g. Fourier-space fields (issue #191)
• BUG: Communicator::sum on a dynamically sized Eigen::Matrix crashed
  under MPI (unsized result)
• TST: MUGRID_FFT_NO_ND=1 hides pocketfft's N-D transforms so the
  axis-by-axis and general pencil FFT paths run in the test suite