- Removed unnecessary cast check to (*net.TCPConn). When the timer
fires, the connection is already established. Replaced with check
that connection has not been closed.
- Add PING test that checks that pings are sent to TLS connections.
- Changed Go version to 1.7.5 in travis.
- Removed test package from code coverage.
- The number of outstanding PINGs is now reset whenever the server
receives a PONG from the client.
- Updated parser test to check c.pout.
- Added a test to check for unprompted PONGs.
Resolves issue: https://github.com/nats-io/gnatsd/issues/168
