Added sending `inv` message.
Added sending `inv` message.

bankonme/bitcoinjs-server,bitfloor/bitcoinjs-server,javascriptit/bitcoinjs-server,zhangweis/node-jds,dazoe/bitcoinjs-server,dazoe/bitcoinjs-server,bitfloor/bitcoinjs-server,zhangweis/node-jds,dazoe/bitcoinjs-server,javascriptit/bitcoinjs-server,bankonme/bitcoinjs-server,javascriptit/bitcoinjs-server,bankonme/bitcoinjs-server,zhangweis/node-jds