Implement interpolation (without CubicInterpolationCUDA)

pystencils/backends/cbackend.py

pystencils/backends/cuda_backend.py

pystencils/backends/cuda_known_functions.txt

pystencils/cpu/kernelcreation.py

pystencils/data_types.py

pystencils/field.py

pystencils/gpucuda/cudajit.py

pystencils/gpucuda/kernelcreation.py

pystencils/gpucuda/texture_utils.py

pystencils/include/__init__.py

pystencils/interpolation_astnodes.py

pystencils/kernelcreation.py

pystencils/transformations.py

pystencils_tests/test_address_of.py

pystencils_tests/test_data/lenna.png

pystencils_tests/test_data/test_vessel2d_mask.png

pystencils_tests/test_field_coordinates.py

pystencils_tests/test_interpolation.py