#82 Support error responses to INVITE on early BYE

[Tom Smith]

When a BYE is sent on an early dialog, RFC 3261 (15.1.2) says that the UAS MUST respond to any pending requests received for that dialog. This certainly applies to the INVITE. Order of such responses relative to the BYE response is not specified. Need to ensure that:

(1) The SIP port state tracker allows receipt of such responses from a UAS and sending such responses to a UAC.
(2) That SipPortTeardownFSM follows this spec.
(3) That B2BUA fragment(s) follow this spec.

[Tom Smith]

- Verified InviteDialogFSM allows error responses to outstanding requests on early BYE
- Modified SipPortTeardownFSM to send 487 to outstanding requests on early BYE

Sending InviteDialogFSM.ech
Sending SipPortTeardownFSM.ech
Transmitting file data ..
Committed revision 1663.

[Tom Smith]

B2buaSafeFSM terminates after 200/BYE. Since the order of responses is not specified, how do we know when to terminate?

[Tom Smith]

How about waiting for responses to all outstanding requests? We should get 408, but we could put in a delay transition for defensive purposes.