fixes documentation in readme for multiscrape api

Author: vijayanand nandam

README.md

@@ -217,7 +217,7 @@ Scraping multiple torrent info is possible with a static `Client.scrape` method:
 
 ```js
 var Client = require('bittorrent-tracker')
-Client.scrape(announceUrl, [ infoHash1, infoHash2 ], function (err, results) {
+Client.scrape({ announce: announceUrl, infoHash: [ infoHash1, infoHash2 ]}, function (err, results) {
   results[infoHash1].announce
   results[infoHash1].infoHash
   results[infoHash1].complete