XX-11148: Upgrade Jetty to latest (9.1.5)

-upgrade jetty to 9.1.5
-upgrade jasper-compiler, jasper-runtime to 5.5.23
-upgrade slf4j to 1.7.7
-update sipxconfig and cmcprov to use new jetty
-upgrade servlet 2.x spec to servlet 3.1 (includes websocket spec)
(keep existing jetty dep and servlet 2.0 for other projects that use jetty container)
-update sipxconfig-jetty according to new jetty
-update sipxconfig startup script
-fix precommit