linkify all @screen_name and #hashtag

linkify_tweet.js

/*
 * credited to Stephen Granade
 * http://granades.com/
 */
String.prototype.linkify_tweet = function() {
	var tweet = this.replace(/(^|\s)@(\w+)/g, '$1@<a href="http://www.twitter.com/$2">$2</a>');
	return tweet.replace(/(^|\s)#(\w+)/g, '$1#<a href="http://search.twitter.com/search?q=%23$2">$2</a>');
};