export ignored event dates too

app/src/main/kotlin/com/simplemobiletools/calendar/helpers/Constants.kt

@@ -68,6 +68,7 @@ val TRIGGER = "TRIGGER:"
 val RRULE = "RRULE:"
 val CATEGORIES = "CATEGORIES:"
 val STATUS = "STATUS:"
+val EXDATE = "EXDATE:"
 
 val DISPLAY = "DISPLAY"
 val FREQ = "FREQ"

app/src/main/kotlin/com/simplemobiletools/calendar/helpers/IcsExporter.kt

@@ -37,6 +37,7 @@ class IcsExporter {
 
                 fillRepeatInterval(event, out)
                 fillReminders(event, out)
+                fillIgnoredOccurrences(event, out)
 
                 out.writeLn("$STATUS$CONFIRMED")
                 out.writeLn(END_EVENT)
@@ -123,4 +124,10 @@ class IcsExporter {
         }
         return "-P${days}DT${hours}H${remainder}M0S"
     }
+
+    private fun fillIgnoredOccurrences(event: Event, out: BufferedWriter) {
+        event.ignoreEventOccurrences.forEach {
+            out.writeLn("$EXDATE${Formatter.getDayCodeFromTS(it)}")
+        }
+    }
 }