Fix concurrency issue on iOS in fetchAllEvents (#67)
Fix concurrency issue on iOS in fetchAllEvents (#67)

When I fetch x-times all events in different dates very quickly (means before one finish I start fetching another events for another date), results of last finish fetch is set to `RNCalendardEvents.calendarEvents`. In this case events are returned randomly from user perspective.

when I replace `_weakSelf.calendardEvents` with `NSArray *calendarEvents` events are returned correctly.
wmcmahan/react-native-calendar-events,wmcmahan/react-native-calendar-events,wmcmahan/react-native-calendar-events