PETSC works with io; comments and optimisations missing

Petsc works, but no io communication

FE out of work, add modified CN, but not complete. Needs Petsc in addition

Improve write function for result file

fixed a small failure

Merge branch 'master' of https://github.com/Wirkungsfunktional/FDM_Project

add write function and fixed py_prog, added errorplots

Add makefile

added nSG scheme

added main for mpi in class and heat equation as test example.

design of class structure

MPI implementation scheme for FE

Merge branch 'master' of https://github.com/Wirkungsfunktional/FDM_Project

simple solver

Initial commit