* An ActionScript 3 implementation of OAUTH, An open protocol to allow secure API authorization
 * Visit www.oauth.net for further information.
 * Copyright (c) 2009 Dan Petitt (http://coderanger.com). All rights reserved.
 * 
 * Requires as3corelib from http://code.google.com/p/as3corelib/. Copyright Henri Torgemane
 * 
 * Redistribution and use in source and binary forms, with or without modification, 
 * are permitted provided that the following conditions are met:
 *
 * Redistributions of source code must retain the above copyright notice, this list 
 * of conditions and the following disclaimer. Redistributions in binary form must 
 * reproduce the above copyright notice, this list of conditions and the following 
 * disclaimer in the documentation and/or other materials provided with the distribution.
 *
 * Neither the name of the author nor the names of its contributors may be used to endorse
 * or promote products derived from this software without specific prior written permission.
 *
 * THE SOFTWARE IS PROVIDED "AS-IS" AND WITHOUT WARRANTY OF ANY KIND, 
 * EXPRESS, IMPLIED OR OTHERWISE, INCLUDING WITHOUT LIMITATION, ANY 
 * WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.  
 *
 * IN NO EVENT SHALL TOM WU BE LIABLE FOR ANY SPECIAL, INCIDENTAL,
 * INDIRECT OR CONSEQUENTIAL DAMAGES OF ANY KIND, OR ANY DAMAGES WHATSOEVER
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GENERAL IDEA
	1.	The application uses oauth/request_token to obtain a request token from twitter.com. 
	2.	The application directs the user to oauth/authorize on twitter.com. 
	3.	After obtaining approval from the user, a prompt on twitter.com will display a 7 digit PIN. 
	4.	The user is instructed to copy this PIN and return to the appliction. 
	5.	The application will prompt the user to enter the PIN from step 4. 
	6.	The application uses the PIN as the value for the oauth_verifier parameter in a call to oauth/access_token which will verify the PIN and exchange a request_token for an access_token. 
	7.	Twitter will return an access_token for the application to generate subsequent OAuth signatures. 

			The access token, access secret and access PIN need to be persisted for future requests

	
TO AUTHORISE APPLICATION
Create an instance of the class and set it up for your application:
	a. setup the oauthDomain, consumerKey, consumerSecret and usePinWorkflow properties
		 (if necessary, modify the requestTokenFragment, authorizeFragment, accessTokenFragment for the consumer you are using)
	b. setup listeners for OAuthEvent.ON_REQUEST_TOKEN_RECEIVED, OAuthEvent.ON_REQUEST_TOKEN_FAILED, ON_ACCESS_TOKEN_RECEIVED and ON_ACCESS_TOKEN_FAILED
	c. call requestToken()
	d. on the ON_REQUEST_TOKEN_RECEIVED listener you can then ask the application user whether they are happy to be redirected to the consumer web site
		 to authorise the application's access to the user's account. If okayed by the user, call requestAuthorisation()
	e. The user will be given a pin number which they should enter into your application, after which you call requestAccessToken( pinNumber );
	f. on the ON_ACCESS_TOKEN_RECEIVED listener you will get the access token/secrets that you need to persist to storage for all future secured calls to the 
		 consumer, these are the accessPin, accessToken, accessTokenSecret (but you will also need the application ConsumerKey and ConsumerSecret for future calls)


TO CALL CONSUMER WITH SECURED SIGNED REQUESTS
Once authorised, create a new instance of the class and set it up with the persisted access tokens and call the getSignedURI( method, uri, postData ) to get the signed secured
data to send to the consumer: 

For example...
	var twitauth:OAuthManager = new OAuthManager();
	twitauth.usePinWorkflow = true;
	twitauth.accessPin = accessPin;
	twitauth.accessToken = accessToken;
	twitauth.accessTokenSecret = accessTokenSecret;
	twitauth.consumerKey = applicationConsumerKey;
	twitauth.consumerSecret = applicationConsumerSecret;
	twitauth.oauthDomain = "twitter.com";
	var postData:String = twitauth.getSignedURI( "POST", "http://twitter.com/statuses/update.xml", "status=" + encodeURIComponent(tweet.text) );

	var httpService:HTTPService = new HTTPService;
	httpService.url = "http://twitter.com/statuses/update.xml";
	httpService.useProxy = false;
	httpService.method = "POST";
	httpService.contentType = "application/x-www-form-urlencoded";
	httpService.addEventListener( "result", httpPostResult );
	httpService.addEventListener( "fault", httpPostFault );
	httpService.send( new QueryString( postData ).toPostObject() );