A commit with Confirmable support:

A commit with Confirmable support:
Patch set 1 which supports:
1) Sending a delayed response when the request is received as multicast, tested only on linux.
2) Sending confirmable requests.
3) Sending confirmable observer notifications.
4) Sending nonconfirmable observer notification with support of detecting client leaving.
5) Added support for client to send RESET instead of regular GET.
6) Error handling in cases of failed retransmissions.
7) Code reorganizations and refactoring.

Patch set 2:
1) Response to code reviews

Patch set 3:
1) Rebased on master

Patch set 4:
Removed tabs.

Change-Id: I502168bf71c7253f3d4b64b9c2edfe40b1cd8d7a