Highlight any characters that are over our limit

![screen shot 2014-04-09 at 11 44 30 am](https://cloud.githubusercontent.com/assets/116327/2659674/0b691294-c017-11e3-9284-7cae46c15e9f.png)

I'm using `LightRed` color, since we want this to be annoying and in your face. But I'm open to other color suggestions, in consideration with other color schemes.