WIP: abaqus handling (#1600)

- reads/write shell elements.
  The writing is currently rather "bulky" in that it does not collect
  according to element types.

- can read solids, but extraction is not implemented.
  Simply ignore *Surface until that is resolved.

- surface sampled output:

  WIP with separate geometry and values.
  Values are dumped in column format (raw) for scripting until
  things are finalized.