• Coordinates: add GetSymmetryBoundaries function to query boundary type

  modelled after SymBase's function of the same name

• Interpolate2: distinguish between physical and symmetry outer boundaries

• Coordinates: reallow interpatch boundary interpolation for all Thornburg04

• Interpolate2: fix classifying points as symmetry boundary

  symmetry-ness beats physical-boundary-ness so that we do not try to interpolate but let the symmetry code fill in the data which requires no stencil operation

Ticket is here: https://bitbucket.org/einsteintoolkit/tickets/issues/2030/multi-block-boundaries-leave-uninitialized