Improved handling of Gmsh mesh format reading

[tcew]

Issue: User provided msh file not properly read by meshParallelReaderQuad2D

Details: To explain this, the boundary faces in the msh file are given for instance by
5 1 2 0 1 1 5
6 1 2 0 1 5 6
7 1 2 0 1 6 7
8 1 2 0 1 7 8

We check to see the element type from the second column

   sscanf(buf, "%*d%d", &ElementType);

    if(ElementType==1){ // boundary face                                                                                                                                                                                             
      sscanf(buf, "%*d%*d %*d" hlongFormat "%*d" hlongFormat hlongFormat,
             boundaryInfo+bcnt*3, &v1, &v2);
      boundaryInfo[bcnt*3+1] = v1-1;
      boundaryInfo[bcnt*3+2] = v2-1;
      ++bcnt;
    }

We ignore the "2" column, which is the number of tags associated with the edge, which is a strong assumption.

In this case we read the tag from the wrong place (the zero) instead of the one. I am not sure how to fix this given that the format is somehow different but the same.

[nnnunnn]

Issue: User provided msh file not properly read by meshParallelReaderQuad2D

I'll explore. Please send or link the offending file.