* Updated Maven plugins to versions that support JDK 9.
* Added jdk9 profiles to the build files.
* Introduced modules jetty-alpn-java-client and jetty-alpn-java-server
containing a pure JDK 9 implementation of ALPN.
* Wired ALPN connection factories (client and server) to use the proper
ALPN implementation based on the JDK platform version (8 or 9).
+ Mappings are persisted if added to the NativeWebSocketConfiguration
before that configuration is started. Otherwise they are cleared
out on configuration.stop() lifecycle (like before)
+ Making WebSocketServletFactory always load a new
WebSocketServerFactory
+ Making WebSocketServerFactory need a ServletContext
to construct it, if appropriate (the WebSocketHandler
approach doesn't use a ServletContext)
+ NativeWebSocketConfiguration is now a bean of
ServerContainer
+ Removed WebSocketServletFactory.init(ServletContext) method
+ Renamed WebSocketServletFactory.init() to .start()
+ Renamed WebSocketServletFactory.cleanup() to .stop()
+ CDI & Websocket now works
+ Using a ServletContextListener now works
+ DecoderFactory and EncoderFactory now work
+ WebSocketServerContainerInitializer now initializes the
MappedWebSocketCreator, WebSocketServerFactory, and
ServerContainer directly, but puts the components needed
by WebSocketUpgradeFilter into ServletContext attributes
that it can obtain in its own init()
+ Added optional org.eclipse.jetty.websocket.jsr356.addDynamicFilter
init-param/attribute key to disable/enable the automatic addition
of the WebSocketUpgradeFilter during JSR356 init (to allow
WEB-INF/web.xml specified filter to operate instead)
+ Added WebSocketServerContainerINitializer.isEnabledViaContext()
to make testing the init-param and attributes more generic
+ Tests for WebSocket upgrade now evaluates the request
from least common feature to most common feature, so as
minimize the testing of the request object on every request
