Disabling xoauth2 since it doesn't appear to be working with gmail

From what I can see, the google xoauth2 specs require the token to be an access token, rather than just the user's password.

But I could be wrong, has the xoauth2 auth been tested and found to be working?
Merge pull request #76 from titaniumlou/patch-1

Disabling xoauth2 since it doesn't appear to be working with gmail