Add require for EventEmitter.

Author: fool2fish

lib/data/index.js

@@ -2,6 +2,7 @@ var fs = require('fs')
 var path = require('path')
 var utilx = require('utilx')
 var inherits = require('util').inherits
+var EventEmitter = require('events').EventEmitter
 
 var logger = require('../logger')
 var common = require('../common')