This addresses the issue that the `Request.authenticate` function cannot be used to authenticate on servers that don’t send an authentication challenge.

Set indentation settings to four spaces at the project level

Feature - Non-Final SessionDelegate

Fixed minor typos in README

Requests with invalid credentials should terminate with a 401 code

As defined in RFC 7235 https://tools.ietf.org/html/rfc7235#section-3.1

Fixes #1159

Fixed redirect with completion property not being called