Facia tool: headline & mode restrictions

* allows fronts to be configured to strictly disallow long headlines and live-mode edits (eg breaking-news.)
  
![screenshot3](https://cloud.githubusercontent.com/assets/1147913/3845539/9482b162-1e53-11e4-98cf-b04beb4af406.png)

![screenshot2](https://cloud.githubusercontent.com/assets/1147913/3845538/929c3b84-1e53-11e4-975b-2813f36842d4.png)

* adds a headline length indicator (red when over 90)

![screenshot](https://cloud.githubusercontent.com/assets/1147913/3845537/8fd29df8-1e53-11e4-8267-d2cda8bc81c0.png)