* Optional latitude and longitude to darksky sensor
allow configuration of latitude and longitude in the darksky sensor.
falls back to home assistant coordinates if latitude/longitude not
specified.
* lat/long as inclusive on schema. removed None check for lat/long in setup_platorm
altered schema to require latitude and longitude configured as a pair.
removed None check on latitude and longitude since values will fall back
to hass config if not present
* adhere to line limit of 79 characters
adhere to line limit of 79 characters