Compared to the initial version of `pythonradex`, this version is an almost complete makeover. The most important changes compared to the initial version are:
- massive speedup thanks to:
- avoiding unnecessary or repetitive calculations
- use of the [`numba`](https://numba.readthedocs.io/en/stable/#) package for just-in-time compilation of critical parts of the code
- use of ng-acceleration
- support of internal dust continuum radiation field
- support of overlapping lines (implementation of the scheme presented by Rybicki & Hummer 1992)
- user can request spectra as output