Ability to add flags for initial session/login.

Pretty much if you have SSO/SAML, you end up with a redirect page..  You can use "?os_authType=basic" to help.

https://developer.atlassian.com/docs/atlassian-platform-common-components/rest-api-development/rest-and-os_authtype

Just noting this as an issue, I'll try to come up with a pull request to handle this which hopefully doesn't suck, but it's on the bottom of my to-do list at the moment.
