VTKXML: Small fix to export von Mises stress correctly.
unv2oofem: Added support to read TrPlaneStress2DXFEM elements from
Abaqus format.
XFEM: Added support to extract the displacement jump along a crack.
Merge branch 'master' of https://github.com/Micket/oofem
Created module to export some data in Gnuplot format. Also renamed folder for interface materials.
AbaqusUserMaterial: Added option to choose if numerical or analytical
tangent should be used.
XFEM: Moved some output from EnrichmentItem to GnuplotExportModule.
Merge branch 'master' of https://github.com/Micket/oofem