Authentication Updates

Hello,
   During internal productization, I added several feature to Ice.  This is a commit of those changes:

- addition of "ice.use_blended" as a toggle between blended/unblended.  Default behavior is blended.
- addition of a new route to redirect to the application context when someone hits '/'
- addition of an authentication framework.  default is not enabled
- addition of a passphrase protected login plugin
- addition of a SAML login plugin
- updated README for these additions.

The first commit around services with '/' in the name was later removed with https://github.com/Netflix/ice/issues/100 being submitted in its place.

Lots of changes I know.

Thanks,

Anthony