When no tabs are shown, show the edited filename in the toolbar

- Fixed #417
- Also change font size of the tabs label

@devoncarew

See screenshot:
![screen shot 2013-12-09 at 11 31 18 pm](https://f.cloud.github.com/assets/332168/1712225/20a2f020-616d-11e3-9a27-b3b6f008b071.png)