Fixed issue with selecting Instagram images.
Based on the log files, it appears that Instagram changed their auth flow and are now using some endpoints from Facebook. I was able to fix it by adding the following urls to the allowedUrlPrefix.plist:
https://s-static.ak.facebook.com/connect/xd_arbiter/
https://www.facebook.com/connect/ping
Merge pull request #57 from GiantThinkwell/bug/UpdateAllowedUrlPrefixForInstagram

Fixed issue with selecting Instagram images.