Fix php warnings about illegal offset.

See https://github.com/friendica/friendica/issues/1105
Merge branch 'master' into develop
New font awesome version, applying all changes from the hackathon
Highlighting of notified items works again.
Adjusted navigation.

* Admin is now next to the user menu
* Introductions, contacts, messages now inside user menu
* Notification bell is empty when no notifications
Merge pull request #3 from Beanow/release/nav-structure-pre-release

Navigations structure pre-release