Fixed calendar inclusion

With no return of the object, the main program couldn't verify the
proper addition of the event in the calendar.

calendar_processor.js

@@ -1,5 +1,5 @@
 // connects to Google Calendar and creates an event in the default calendar
 // of the account
 function create_event(title, date){
-    CalendarApp.getDefaultCalendar().createAllDayEvent(title, date);
+    return CalendarApp.getDefaultCalendar().createAllDayEvent(title, date);
 }