Implement heartbeat message in obfsproxy
We should add a heartbeat message to obfsproxy that says how long it's running and that gives a connection count. That's a good feedback for operators, and it's a safer way to get some stats on obfsproxy usage that operators can report to us.
The next iteration would be to include unique addresses of connecting clients. And then we might want to add a GeoIP database and report both connections and unique IPs by country. But that's the future.