FIX: Corrected computation of basis functions and basis function
derivatives for biquadratic interpolation.
Implemented biquadratic 9-node quadrilateral. (Many functions have only
been copied from the 8-node quad though.)
Fixed principal stresses in 2D and 3D in vtk output.
Added missing zeroing which caused errors when not using BLAS.
Implemented two new material models: isotropic St.Venant-Kirchhoff and
orthotropic (transversely isotropic) St.Venant-Kirchhoff.
Also fixed index bug in qtrspace.C
Merge remote-tracking branch 'upstream/master'
Merge pull request #1 from erisve/master

Isotropic and orthotropic St.Venant - Kirchhoff material models now available
Fixed check to see if an interface has delaminated.
Merge branch 'master' of github.com:Micket/oofem
Added export of every integration rule to the GPExportModule