Support air pollution APIs
This release brings support for OpenWeatherMap's air pollution APIs (currently in beta):
- Carbon Monoxide Data
- Ozone Data
- Sulfur Dioxide Data
- Nitrogen Dioxide Data
Big thanks to @tomtomklima for kicking this off by working on the carbon monoxide API in #138!
We also fixed a bug related to missing wind directions when using the weather group API reported by @KarelWintersky in #137.