Let sideset inherit name of nodeset when calling build_side_list_from_node_list().
Misc. improvements to Abaqus reader

* Support reading T3D2 (truss) and S3R (three node large strain triangular shell element)
* Associate nodeset, sideset, and elset names with their respective IDs.
* Delete whitespace characters, including newlines, when extracting labels.
* Handle reading multiple *NODE sections.
* Don't set the mesh dimension based on elements seen, instead set the
  proper flags in the elems_of_dimension vector.
* Add the max_elem_dimension_seen() function and use it to set the
  Mesh dimension. This function should probably be moved to the
  MeshOutput base class.
Support reading lower-dimensional elements for BCs

* Use a multimap to assign assign sideset ids.
* Skip assigning subdomain ids to lower-dimensional elements.
* Delete lower-dimensional elements in Abaqus reader.
* Associate sideset name with ID.
Read and store NSET names while reading *NODE sections.
Skip reading *NODE and *ELEMENT OUTPUT sections.
Deleting print/debugging statements.