Transports: Convert internal state to enums (ticket #1458)

router/java/src/net/i2p/router/CommSystemFacade.java

router/java/src/net/i2p/router/Router.java

...va/src/net/i2p/router/transport/CommSystemFacadeImpl.java

router/java/src/net/i2p/router/transport/Transport.java

router/java/src/net/i2p/router/transport/TransportImpl.java

...r/java/src/net/i2p/router/transport/TransportManager.java

...java/src/net/i2p/router/transport/ntcp/NTCPTransport.java

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

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