Started on HtmlServiceClient and unit tests to prove session's ReferrerUrl always works.
Merge branch 'master' into html-client-experiments
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).
Merge branch 'auth-session-referrer-issue' into html-client-experiments
Added ability to configure underlying WebRequest.AllowAutoRedirect, as the unit test needed to disable this to get the original response with the Location header.