Update darksky.coffee to retrieve the correct summaries

Just an update to get the right data out of the V2 API (https://developer.forecast.io/docs/v2), specifically:

* minutely: A data block (see below) containing the weather conditions minute-by-minute for the next hour. (This property’s name should be read as an adjective—analogously to “hourly” or “daily” and meaning “reckoned by the minute”—rather than as an adverb meaning “meticulously.” Yes, we know that this is not proper English. No, we will not change it. Complaints to this effect will be deleted with utmost prejudice.)

* hourly: A data block (see below) containing the weather conditions hour-by-hour for the next two days.