Clean up and Bug Fixes

.gitignore

.gitlab-ci.yml

doc/notebooks/03_tutorial_datahandling.ipynb

doc/notebooks/demo_plotting_and_animation.ipynb

pystencils/backends/cbackend.py

pystencils/cache.py

pystencils/cpu/cpujit.py

pystencils/cpu/vectorization.py

pystencils/data_types.py

pystencils/datahandling/datahandling_interface.py

pystencils/datahandling/parallel_datahandling.py

pystencils/datahandling/serial_datahandling.py

pystencils/fd/derivation.py

pystencils/jupyter.py

pystencils/math_optimizations.py

pystencils/session.py

pystencils_tests/test_aligned_array.py

pystencils_tests/test_bit_masks.py

pystencils_tests/test_boundary_indexlist_creation.py

pystencils_tests/test_create_kernel_backwards_compability.py