make most classes package local; stub out a session destroy message; javadoc

...er/java/src/net/i2p/router/transport/udp/ACKBitfield.java

router/java/src/net/i2p/router/transport/udp/ACKSender.java

.../java/src/net/i2p/router/transport/udp/DummyThrottle.java

...rc/net/i2p/router/transport/udp/EstablishmentManager.java

...c/net/i2p/router/transport/udp/InboundEstablishState.java

...net/i2p/router/transport/udp/InboundMessageFragments.java

...src/net/i2p/router/transport/udp/InboundMessageState.java

...src/net/i2p/router/transport/udp/IntroductionManager.java

...r/java/src/net/i2p/router/transport/udp/MessageQueue.java

...ava/src/net/i2p/router/transport/udp/MessageReceiver.java

.../net/i2p/router/transport/udp/OutboundEstablishState.java

...et/i2p/router/transport/udp/OutboundMessageFragments.java

...rc/net/i2p/router/transport/udp/OutboundMessageState.java

...va/src/net/i2p/router/transport/udp/OutboundRefiller.java

.../java/src/net/i2p/router/transport/udp/PacketBuilder.java

.../java/src/net/i2p/router/transport/udp/PacketHandler.java

...r/java/src/net/i2p/router/transport/udp/PacketPusher.java

router/java/src/net/i2p/router/transport/udp/PeerState.java

...uter/transport/udp/TimedWeightedPriorityMessageQueue.java

...er/java/src/net/i2p/router/transport/udp/UDPEndpoint.java