Hello all,

I have made some new PRs to the ever popular iOS OAuth2 library. Since all the open PRs currently on there are mine, I figure it might be a good time to review:

* #63 - This is maybe the most complex of the lot. It adds the ability for developers authenticating with Google to share refresh credentials between a backend server and mobile client
* #67 - This brings the library up to date in it's use of SFSafariViewController over the external Safari app. A nice-to-have would be a restriction on Google accounts to *never* be able to use the embedded webview, as Google will no longer accept auth requests this way
* #68 - This adds better error handling, bringing the library in compliance with standard OAuth2 error data
* #69 - This adds the ability for developers to control when the auth web view is dismissed. This is especially useful when the view is part of a navigation stack and not just the root view controller.
* #70 - This fixes potential crashes for Config objects that don't define a token revocation endpoint.
* #71 - This fixes a number of spelling errors, including changing the name of the TrustedPersistentOAuth2Session class.

I hope these can be reviewed soon, as many of them are straightforward in their goal and implementation.

As an aside, I will be leaving my current job tomorrow and switching to a non-mobile development role. This means I will have less time to dedicate to the project (and by extension follow-up work for my PRs). I hope my contributions have been helpful to at least a few of you.

Best,
Michael Doo
410 Labs, Inc.