Initial weather service.

This commit introduces two new classes:

 1. GCalWeatherService
 2. GCalWeatherInfo

GcalWeatherservice picks-up the current location and periodically
fetches weather reports represented by GcalWeatherInfo.

The weather part is not complete yet.

src/gcal-weather-service.h

@@ -0,0 +1,47 @@
+/* gcal-weather-service.h
+ *
+ * Copyright (C) 2017 - Florian Brosch <flo.brosch@gmail.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef GCAL_WEATHER_SERVICE_H
+#define GCAL_WEATHER_SERVICE_H
+
+#include <glib-object.h>
+#include <glib.h>
+
+G_BEGIN_DECLS
+
+#define GCAL_TYPE_WEATHER_SERVICE (gcal_weather_service_get_type())
+
+G_DECLARE_FINAL_TYPE (GcalWeatherService, gcal_weather_service, GCAL, WEATHER_SERVICE, GObject)
+
+
+GcalWeatherService* gcal_weather_service_new                (guint max_days,
+                                                             guint check_interval);
+
+void                gcal_weather_service_run                (GcalWeatherService *self);
+
+void                gcal_weather_service_stop               (GcalWeatherService *self);
+
+guint               gcal_weather_service_get_max_days       (GcalWeatherService *self);
+
+guint               gcal_weather_service_get_check_interval (GcalWeatherService *self);
+
+
+G_END_DECLS
+
+#endif /* GCAL_WEATHER_SERVICE_H */
+