* Added cover.group platform
* Added async/await, smaller changes
* Made (async_update) methods regular methods
* Small improvements
* Changed classname
* Changes based on feedback
* Service calls
* update_supported_features is now a callback method
* combined all 'update_attr_*' methods in 'async_update'
* Small changes
* Fixes
   * is_closed
   * current_position
   * current_tilt_position
* Updated tests
* Small changes 2