Started on HtmlServiceClient and unit tests to prove session's ReferrerUrl always works.
Finished the unit test (and related core library functionality) to get a failing test without the AuthService session reference fixes and a passing test with the fixes (branch: auth-session-referrer-issue).
Added ability to configure underlying WebRequest.AllowAutoRedirect, as the unit test needed to disable this to get the original response with the Location header.
Cleaned up the unit test to make its intentions clearer.
Simple workaround for auth service using old session instance, however the bug may crop up in other places later.
Cleaned up some sample request-response data I was using for the HtmlClient.
Merge branch 'html-auth-session-referrer-issue' into html-auth-session-referrer-workaround
Added code documentation to warn about the session changing side effects.
Merge branch 'master' into html-auth-session-referrer-workaround

Conflicts:
	tests/ServiceStack.WebHost.Endpoints.Tests/AuthTests.cs
Merge pull request #399 from Its-Tyson/html-auth-session-referrer-workaround

(UPDATED) AuthService doesn't obey new session's ReferrerUrl for html requests