fixed #28 and other small node.js issues

index.js

@@ -1,4 +1,7 @@
 var web3 = require('./lib/web3');
+var ProviderManager = require('./lib/providermanager');
+web3.provider = new ProviderManager();
+web3.filter = require('./lib/filter');
 web3.providers.WebSocketProvider = require('./lib/websocket');
 web3.providers.HttpRpcProvider = require('./lib/httprpc');
 web3.providers.QtProvider = require('./lib/qt');