SIP Functionality
From VoIPER
- The following need to be added to sip_agent.py for state traversal and server testing.
- SIP REGISTER - done
- SIP INVITE - done
- Write demo test case of
- REGISTER - done
- INVITE -> CANCEL - done
- The following SIP verbs/responses will also need to be added for future testing but are not immediately required
- BYE
- SUBSCRIBE
- NOTIFY
- 200 OK
- Port the SIP registrar to the new backend

