Merge pull request #670 from DhruvSaraswat/master

Updated a few expired links in README

README.md

@@ -291,18 +291,18 @@ See more examples in the demo application: [ViewController.swift](/Demo/Common/V
 * [Twitter](https://dev.twitter.com/oauth)  
 * [Flickr](https://www.flickr.com/services/api/auth.oauth.html)  
 * [Github](https://developer.github.com/v3/oauth/)  
-* [Instagram](http://instagram.com/developer/authentication)  
+* [Instagram](https://developers.facebook.com/docs/instagram-basic-display-api/guides/getting-access-tokens-and-permissions)  
 * [Foursquare](https://developer.foursquare.com/overview/auth)  
 * [Fitbit](https://dev.fitbit.com/build/reference/web-api/oauth2/)  
 * [Withings](http://oauth.withings.com/api)  
-* [Linkedin](https://developer.linkedin.com/docs/oauth2)  
-* [Dropbox](https://www.dropbox.com/developers/core/docs)  
-* [Dribbble](http://developer.dribbble.com/v1/oauth/)
+* [LinkedIn](https://docs.microsoft.com/en-us/linkedin/shared/authentication/authentication)  
+* [Dropbox](https://www.dropbox.com/developers/documentation/http/documentation)  
+* [Dribbble](https://developer.dribbble.com/v2/#authentication)
 * [Salesforce](https://developer.salesforce.com/docs/atlas.en-us.api_rest.meta/api_rest/)
 * [BitBucket](https://confluence.atlassian.com/bitbucket/oauth-on-bitbucket-cloud-238027431.html)
 * [GoogleDrive](https://developers.google.com/drive/v2/reference/)
 * [Smugmug](https://smugmug.atlassian.net/wiki/display/API/OAuth)
-* [Intuit](https://developer.intuit.com/docs/0100_accounting/0060_authentication_and_authorization/oauth_management_api)
+* [Intuit](https://developer.intuit.com/app/developer/qbo/docs/develop/authentication-and-authorization)
 * [Zaim](https://dev.zaim.net/home/api/authorize)
 * [Tumblr](https://www.tumblr.com/docs/en/api/v2#auth)
 * [Slack](https://api.slack.com/docs/oauth)