- Add functions to convert between specific humidity and humidity ratio (aka mixing ratio).
- Add functions to convert to dry bulb temperature or humidity ratio from enthalpy.
- Restrict minimum value of humidity ratio to `1e-7`
- Fix bug with `GetTDewPointFromVapPres` not always converging due to discontinuity about the freezing point of water in `GetSatVapPres` formulae.
- General `README.md`/docs improvements.