Support Exchange 2019

Merge pull request #45 from nylas/support-exchange-2019

Support Exchange 2019

Improve error handling for calendar items with occurrence item ids

Merge pull request #41 from nylas/check-occurrence-id

Improve all day event handling & add GenericDateField class

Merge pull request #39 from nylas/all-day-event-handling

Modify the CalendarItem logic to better account for all day events

Add FreeBusyAccount class

Merge pull request #38 from nylas/freebusyaccount

Add a new FreeBusyAccount class object

Implement support for OccurrenceItemId

Implement support for OccurrenceItemId

Update urllib in util to be Python 2/3 compatible

Implement support for OccurrenceItemId

This identifier field allows us to indicate a specific occurrence within
a recurring series so that we can make individual changes to it. You can
also update occurrences with their direct item id, but unless you're
storing every single occurrence on your end, you're not going to have
the item id for every occurrence. The OccurrenceItemId identifies an
occurrence via the master event's item id and the instance number of the
occurrence within the series.

Add support for Office365 OAuth

Merge pull request #33 from nylas/add_oauth_support

Add OAuth support to Exchangelib

Remove logic to include timezone fields on event updates

Merge pull request #32 from nylas/annielcook/remove-tz-logic

Remove logic to pass timezone fields with CalendarItem updates

Add ExtendedProperty flag for MessageItems

Merge pull request #31 from nylas/add-flagging-extended-property

Add a flag ExtendedProperty for MessageItems

Modify to_xml

Merge pull request #29 from nylas/raw-data

Modify to_xml method so that we can include/exclude read_only_fields