Essentially equal to 0.9.20 https://github.com/radis/radis/pull/39
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Major changes:
- Implemented Density Line Mapping (DLM) resulting in ~x100 performance improvement. See detail in 37 , 38
Minor changes:
- possible to use an HITRAN .par file directly in `calc_spectrum(databank='blabla.par') `
- updated docs