Adds OpenID RP to WebAPI sample so it's a real login.
Adds an explicit role requirement for WebAPI clients.
Fixes up user rejection cases.
Unit test compile error fixes.
Switched Channel to receiving messages via HttpRequestMessage as well.
A few more fixes.
Changed all ASP.NET async void event handlers to use RegisterAsyncTask, which avoids bugs in ASP.NET.
OpenIdOfflineProvider and RP now work together.
Switched OpenIdOfflineProvider to use HttpSelfHostServer.