Adjust size of Bitcoin address on small screens

**Ready for review again**

**Edit March 18**
Instead of decreasing the font-size we’ll just break the word when the text starts to overflow the table cell, per @seanlinsley’s suggestion.

![screen shot 2014-03-18 at 6 39 08 pm](https://f.cloud.github.com/assets/65468/2454617/545c5766-aeee-11e3-8e3a-293dd4c23fd6.png)

**Old post**

Fixes #2150. Prevents a horizontal scrollbar from appearing viewing profiles with Bitcoin addresses (mostly on iPhones). I decreased the size instead of trying to cut it off with an ellipsis because the implementation is a lot easier and some people may reference addresses by the last few digits.

![screen shot 2014-03-16 at 7 10 27 pm](https://f.cloud.github.com/assets/65468/2432331/2d7eee5e-ad60-11e3-8e3d-585592c28939.png)