[minor] Expose version on module

Author: indexzero

lib/node-http-proxy.js

@@ -32,6 +32,11 @@ var util = require('util'),
     ProxyTable = require('./proxy-table').ProxyTable,
     maxSockets = 100;
 
+//
+// ### Version 0.4.0
+//
+exports.version = [0, 4, 0];
+
 //
 // ### function _getAgent (host, port)
 // #### @host {string} Host of the agent to get