1.6.0

1. Add support for Celestia PLUS subscription service
2. Add support for custom font
3. Add support for special categories for add-ons
4. Include Celestia PLUS subscription information when sending feedbacks

celestiamobile/Celestia@662e9ac
celestiamobile/CelestiaLocalization@f4dc47f
CelestiaProject/CelestiaContent@8e28c7b
celestiamobile/CelestiaCore@1ff7901