HUE-1687 [core] SAML backend with simple redirect logout
HUE-1689 [core] The wrong Browser locale is used

- Need po and mo files for en locale code.
- Force add Django-1.4.5
HUE-1691 [help] Revamp a bit the style

Changed Hue arch and topbar image
Styled titles
Removed margin and added top border
HUE-1692 [core] Add trademark on About page

Added tm and trademark message