Test de-flakiness attempt

Update surefire to latest and set travis to emit maven version.

Only use one MockSpdyPeer in SpdyConnectionTest and close its executor.

Consistency in HttpURLConnection tests.

Bump so and read timeouts in ConnectionPoolTest.
Merge pull request #490 from adriancole/close-test-peers

Use latest junit maven config and close test resources
Update to spdy/3.1 and ignore old spdy frames.