improve handling of sampled meshed surfaces

• Rename starcd input files. Pending name collision between the STARCD cel/vrt/inp naming and that of ABAQUS (.inp).
• Abaqus input for shells elements
• Abaqus output for shells elements
• Abaqus input of element-based surfaces
• Abaqus output of element-based surfaces? Not sure how possible this is
• Prevent automatic triangulation (triSurface behaviour) when reading surfaces for sampling
• Preserve original surface face ids for output
• Handling of surface "zones" on output might need improvement. For starcd these are the cellTableId. For nastran, a PID (property Id). For Abaqus numbers don't appear to be used, just the names, but these are currently lost during the sampling.
• Allow sampling on a surface sub-region. Eg, a surface file might have many named sections, but we only want to retain a subset of those.