renamed mpie_spectral2.f90 to mpie_spectral2d.f90 (testing file, not properly working at the moment)
changed file extension and variable names in mpie_spectral.f90 and mpie_spectral_interface.f90 from "mesh" to "geom". Removed direct output from mpie_spectral.f90, all output is now base on materialpoint_results(:,1,:)
changes on mpie_spectral.f90:
new structure, changed variable names, now using defgrad instead of disgrad, cleaned up, removed augmented Lagrange.
ToDo: Implement Augmented Lagrange again (but then a working version), implement Large strain, think about complex-to real-transform backwards, try to implement MP-support