Kerberos SSO Update

When going back from SSO to database mode, SSO was still
being attempted. Code was looking at the wrong configuration
variable for authentication mode.
Merge hidden_span_if and hidden_div_if

Can now use hidden_tag_if for good and evil
Merge pull request #748 from kbrock/hidden_div_if

Merge hidden_span_if and hidden_div_if
Merge pull request #747 from abellotti/single_signon_update

Kerberos SSO Update