I2CP:

  - Add support for hostname lookups over I2CP with new
    HostLookup and HostReply messages.
  - Move username / password from CreateSession
    to GetDate for early authentication;
    this is an incompatible chage.
    Outside router context with authentication enabled,
    new clients will not work with old routers.
    Early authentication is not yet enforced, enable with
    i2cp.strictAuth=true. Will change default to true in a later release.
  - Block all actions before authentication.
  - Better disconnect messages to clients for diagnostics
  - Improve lookup command, add auth command in i2ptunnel CLI for testing
  - Don't start ClientWriterRunner thread in constructor
  - Don't flush in ClientWriterRunner unless necessary
  - Send GetDate even in SimpleSession outside of RouterContext
  - Improve SetDate wait logic to reduce locks and break out when
    Disconnect received
  - Add Disconnect handler to SimpleSession
  - I2Ping cleanups
  - Javadocs