Refresh the header style and fix the menu.

[bfabio]

• Fix the small screens menu where the items were showing partially.
• Fix the menu not properly displaying the the active tab, in both desktop and small screens version.
• Add link to the database admin area, if it's enabled.
• Refresh the look of the header, using the latest version of bootstrap-italia (v1.3.8).

Before

Active tab

Mobile menu

After

Active tab

Mobile menu

[fmarco]

@bfabio lgtm, rebase on master

[bfabio]

@fmarco Done.

[fmarco]

lgtm