0.3.8
Added work_time entity.
Added entity categories.
Improved handling of entity availability.
Introduced internal_preheater_dutycycle entity (this entity will only be installed if a preheater is present in the ventilation unit).
Added room_temperature entity (for the HRC2 remote; this entity is omitted if not supported by the unit or if the temperature reading is above 70°C or below -40°C).
Fixed the incorrect type for filter_reset and alarm_reset buttons.
Note: Both the internal_preheater_dutycycle and room_temperature entities are untested.