Implement Delegation

[bkircher]

Add example: assign task to multiple mailbox owners, update task, check who has completed it.

[bkircher]

Task delegation is not as easy as I thought initially. Seems that we should take a look at Delegate access and EWS in Exchange in general. Next release.

[bkircher]

In Exchange, you can enable users to access other users’ mailboxes in one of three ways:

• By adding delegates and specifying permissions for each delegate.
• By modifying folder permissions directly.
• By using impersonation.

This ticket is about Delegation.

TODO items:

• Read https://msdn.microsoft.com/en-us/library/office/dn641957(v=exchg.150).aspx.
• Read Delegate Access p41.
• Read Task Delegation and Exhange Web Services p458.
• Implement.
• Add example for task delegation with two distinct mailboxes.
• Implement EWS JS API + example for EWS JS API.