PROTON-192: Pull-up SESSION_WINDOW and DEFAULT_PRIORITY constants from their impls to their respective interfaces.

git-svn-id: https://svn.apache.org/repos/asf/qpid/proton/branches/jni-binding@1436875 13f79535-47bb-0310-9956-ffa450edef68
PROTON-193: Add setPeerHostname/getPeerHostname to Proton Java API and implement with JNI layer only. Test SslTest.test_server_hostname_authentication now
no longer skips when run with proton-c profile.

git-svn-id: https://svn.apache.org/repos/asf/qpid/proton/branches/jni-binding@1436876 13f79535-47bb-0310-9956-ffa450edef68