[SECURITY-793] Add support to fall back to BASIC authentication where SPNEGO not available.
[SECURITY-793] Continuation of implementation of feature to send the Basic header proactively.
Fix for an issue where the NegotiationAuthenticator loses post data
[SECURITY-815]
Potential fix so that the Negotiation will not just return a "401" and
give up in the case where SPNEGO based authentication failed (NTLM, kdc
not available, etc).
[SECURITY-640]
[SECURITY-722] Explicitly set the content type for the login page