Firefox Character encoding issue on the sample size calculator page

Resolves: 
https://github.com/optimizely/marketing-website/issues/518#event-178401484

Was:
![](https://cloud.githubusercontent.com/assets/5033032/4570371/85e74f84-4f5c-11e4-957e-eaf29a5942f0.png)

Now:
![screen shot 2014-10-14 at 5 39 08 pm](https://cloud.githubusercontent.com/assets/2864449/4638998/d70d1f8c-5403-11e4-8154-839ee4bacd19.png)

Not tested in IE. @dtothefp could you pull and look at this for me? I'll work on getting a VM set up.
@stewsmith probably better to use em's here