Connect to GraphSpace using only auth token

[JingVT]

This pull has solved connection to graphspace using auth_token. But it requires user's email address as well. We want user can connect to graphspace using only auth_token. We can use base64.b64decode(auth_token) to get "username:password" where username and password are splitted by ':', so we can get username from it.
Something need to consider:

1. We assume all emails are valid email. Because we assume this confirm email pull has been merged.
2. Does username, i.e. email, include ' : ' ?
3. If username includes ':', then we need to find a new character not allowed in email to replace ':'. One option is '@'.