Visually show visited links in trails and containers

- [new] What it says if you look up

/cc @kungpochicken 

![screen shot 2013-11-20 at 17 48 34](https://f.cloud.github.com/assets/85783/1584453/56a12d38-520c-11e3-9244-65abe68a1475.PNG)

![screen shot 2013-11-20 at 17 48 21](https://f.cloud.github.com/assets/85783/1584456/58d51db2-520c-11e3-8463-2c13ba2b2fe1.PNG)

![ ](http://i.imgur.com/OQoNOLI.gif)