Added alternative piece of code for making the conversion from dS/dE -> dP/dF (for StructuralMaterial) on index form. New code is only preliminary and seems to be a bit slower but debugging is much simpler.
Fixed bug in Shell7BaseXFEM when computing cohesive forces.
Moved interface materials and elements to subfolders under materials and elements respectively. Also moved Shell7Base derived elements to a Shells subfolder.
Started working on a staggered solver for structural problems. Currently in development phase.
Forgot to add the actual new files in the previous commit.
Added several subfolders to the sm module to make it more easy to navigate.
Merge branch 'master' of https://github.com/JimBrouzoulis/OOFEM_Jim
Working on a staggered solver combined with a modified engineering module. Nothing working so far.
Merge branch 'master' of https://github.com/JimBrouzoulis/OOFEM_Jim

Conflicts:
	src/sm/CMakeLists.txt
Added "../sm/" to alot of include statements.
Added method giveSubMatrix to extract a sparse sub matrix from another sparse matrix. Only implemented for symmetric Skyline class.
Also fixed a bug in one of the constructors for the skyline matrix.
Updates to staggered solver nad removal of intermediate files used for development.
Updates for Shell7BaseXFEM regarding handling of cohesive zones.
Merge https://github.com/Micket/oofem

Conflicts:
	src/sm/Elements/Shells/shell7basexfem.C
Did some optimization of the code in Shell7BaseXFEM.
Modified IntElLineX to handle axisymmetry according to the modifications made in the deprecated elements.
When the OOFEG code has been incorporated into the new elements the old ones can be removed.
Updated the element manual concerning interface elements and nonlinear geometry for sm elements.
Merge branch 'master' of https://github.com/JimBrouzoulis/OOFEM_Jim
Fixed broken vtk export for Shell7BaseXFEM
Added some checks for initialization of Delamination EI.