Revision 7292

- implemented a stale re-invite timer 
  - duration is settable via Profile with a default of 40 seconds
  - New onStaleReInviteTimeout callback on InviteSession for applications that are interested
  - default implementation of onStaleReInviteTimeout is to end() the call
  - added new End Reason - StaleReInvite
  - fixes an issues of lingering usages when sending a re-invite, receiving a 1xx response and no final response
- Accept BYE messages in WaitingToTerminate state
- Respond to other requests with a 400 in WaitingToTerminate state