Edit Contacts

Add separate modal window to edit contact. Supported actions are to change the contact display name to a custom display name. If the user is online, there is the ability to sync the contacts display name. 

Removal of contact is moved to this screen.
@theurere: you probably meant something like

```
$scope.session = sessions[id] ? sessions[id].sessions[id] : null;
```

Allthough I agree that `sessions[id].sessions[id]` looks scary ;-)