PyAbsorp

Introduced features:
[FEATURE] Delany-Bazley (with Miki and Allard-Champoux variation) model
[FEATURE] Biot-Allard model
[FEATURE] Johnson-Champoux (with Allard and Lafarge variation)
[FEATURE] Rayleigh
[FEATURE] Functions for calculating air properties (also has a class alternative, highly recommended)
[FEATURE] Material class