Move some data structures away from ByteArray; offsets were always zero
  - New BuildRequestRecord constructors
  - BuildRequestRecord field becomes final byte[222]
  - IV becomes byte[16]
  - Build record becomes EncryptedBuildRecord
Remove extra copy in BuildRequestRecord.encryptRecord()
Remove unused BuildRequestRecord.readOurIdentityMatches()

    - Deprecate unused stream methods and I2NPMessageReader since
      all transports provide encapsulation.
    - Don't throw IOE from byte array methods
    - Use cached null cert in GarlicClove
    - Add method to limit size of buffer to read
    - Don't check checksum at input, in most cases
    - Reuse checksum at output, for unomodified pass-through messages
      (but recalculating it now and logging on a mismatch for testing)
    - Fix DatabaseLookupMessage to internally store the don't include peers as
      a List, not a Set, so it doesn't get reordered and break the checksum
    - Log cleanup
  * NTCP:
    - Zero-copy and limit size when handing buffer to I2NP
    - Log hex dump message on I2NPMessageException, like in SSU
    - Don't close connection on I2NPMessageException

          TunnelBuildReplyMessage into a common base class

      - Add getRecordCount() to TunnelBuildMessage and TunnelBuildReplyMessage
        so they can be extended.
      - New I2NP Messages VariableTunnelBuildMessage and VariableTunnelBuildReplyMessage,
        which contain the number of request slots in them.
      - Convert all static assumptions of 8 slots to getRecordCount()
      - Use the new VTBM if all hops in the tunnel and the OBEP or IBGW of the reply tunnel
        support it, and the tunnel is 4 hops or shorter.
      - Reply to a VTBM with a VTBRM of the same size
      - Make BuildReplyHandler static
      - Convert the currentlyBuilding List to a ConcurrentHashMap to speed reply lookups
        and eliminate a global lock; don't put fallback tunnels in there
      - Add new tunnel.corruptBuildReply stat
      - Various cleanups and javadoc

    Tested as compatible with current network, new messages untested.