Fix typo
Add examples/sip_client based on examples/echo_client
Renaming contents of sip_client from echo_client
Sending a SIP OPTIONS message
Correct the Via header for WS transport
Fixes for sip_client new 0.3 API
Add README for sip_client
Merge pull request #248 from resiprocate/0.3.x-cmake

Fix typo, add sip_client example (SIP over WebSockets)