Call EthereumListener.onRecMessage() and EthereumListener.onSendMessage() respectively if listener is registered with WorldManager.
Merge pull request #166 from biafra23/feature/notify-messages

Call EthereumListener.onRecvMessage() and EthereumListener.onSendMessage()
Remove unused protocol property
Merge branch 'master' of https://github.com/ethereum/ethereumj
Update tests to latest block format
Add SIGNEXTEND op code