Merge branch 'dev-maxwell' into dev0

dev.ipynb

dev.pxd

dev.pyx

pyrost/bin/beam_calc.pxd

pyrost/bin/beam_calc.pyx

pyrost/data_processing.py

pyrost/include/st_gaussian.c

pyrost/include/st_gaussian.h

pyrost/include/st_utils.c

pyrost/include/st_utils.h

pyrost/include/st_waveprop_fftw.c

pyrost/include/st_waveprop_fftw.h

pyrost/include/st_waveprop_np.c

pyrost/include/st_waveprop_np.h

pyrost/simulation/parameters.py