Credits for AirVisual earth rendering

For AirVisual Earth rendering, we'd like to thank:
- Cameron Beccario for its excellent work on the rendering libraries of the earth.nullschool.net project
- The U.S. GFS (Global Forecast System) for its wind data
- Part of weather data comes from openweathermap
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For the pollution data, we're thankful to:
- Each region and country EPA for the great work they do in collecting and publishing the air quality data to the public
- The AirVisual community members who contributes in sharing publicly their outdoor Nodes