calendar: read events synchronized from Gadgetbridge

This is a partial fix for feature request #3707.  This allows synchronized
events (stored in android.calendar.json) to be shown in the app, alongside
the manually entered events and alarm events that are already shown.  Note
only date/time and event title are currently used; other information
available in the synchronized events (e.g. duration, description) are ignored.

apps/calendar/ChangeLog

@@ -19,3 +19,4 @@
       Display Widgets in menus
 0.17: Load holidays before events so the latter is not overpainted
 0.18: Minor code improvements
+0.19: Read events synchronized from Gadgetbridge

apps/calendar/calendar.js

@@ -60,6 +60,12 @@ const loadEvents = () => {
     date.setSeconds(time.s);
     return {date: date, msg: a.msg, type: "e"};
   }));
+  // all events synchronized from Gadgetbridge
+  events = events.concat((require("Storage").readJSON("android.calendar.json",1) || []).map(a => {
+    // timestamp is in seconds, Date requires milliseconds
+    const date = new Date(a.timestamp * 1000);
+    return {date: date, msg: a.title, type: "e"};
+  }));
 };
 
 const loadSettings = () => {

apps/calendar/metadata.json

@@ -1,7 +1,7 @@
 {
   "id": "calendar",
   "name": "Calendar",
-  "version": "0.18",
+  "version": "0.19",
   "description": "Monthly calendar, displays holidays uploaded from the web interface and scheduled events.",
   "icon": "calendar.png",
   "screenshots": [{"url":"screenshot_calendar.png"}],