Added Forecast.io as a weather service, made a few other tweaks

I added Forecast.io as a weather service that is available (```CZForecastioService```), albeit only using latitude and longitude for locations; made the icons given by ```climaconCharacterForDescription:``` in the other two services more specific; and updated ```Climacons.h``` with a few correct icon names ('showers') and a bit more in the comment about the creator of the font and original icons.