Remove witness posts quote icon and normalise styles with new typography

- [fix] Remove quote icon overlapping with text - fixes #3905
- [new] Witness posts scale well (remify all the things)
- [new] Witness typography follows the new settings (using text sans & font-size)
- [new] Document witness embed HTML/CSS oddities

## Before

![screen shot 2014-04-14 at 17 33 29](https://cloud.githubusercontent.com/assets/85783/2697831/f9460c4a-c3f2-11e3-8ded-6acb6cbd3ea0.PNG)

![screen shot 2014-04-14 at 17 33 02](https://cloud.githubusercontent.com/assets/85783/2697836/fd167d14-c3f2-11e3-8dad-a8c691128ecc.PNG)

![screen shot 2014-04-14 at 17 40 11](https://cloud.githubusercontent.com/assets/85783/2697883/7c547400-c3f3-11e3-99e6-cfeb665fa225.PNG)



## After

![screen shot 2014-04-14 at 17 33 14](https://cloud.githubusercontent.com/assets/85783/2697866/460ac9b2-c3f3-11e3-8813-1eef21a28429.PNG)

![screen shot 2014-04-14 at 17 32 55](https://cloud.githubusercontent.com/assets/85783/2697867/49d85f1e-c3f3-11e3-8080-6a3b76bccea3.PNG)


![screen shot 2014-04-14 at 17 40 07](https://cloud.githubusercontent.com/assets/85783/2697887/7fb2697c-c3f3-11e3-877e-bde38478353d.PNG)




![ ](http://media.giphy.com/media/rM5bjhW2omk8M/giphy.gif)