Add style to inline code elements, fixes #7

See #7 

This is how inline code (e.g. `foo`) will be styled with this commit (right click -> open image in new tab for zoom):

![inline code element in text](http://i.imgur.com/4dv6RJ6.png)
---
![inline code element in titles](http://i.imgur.com/khy6HYM.png)

As you can see, the inline code elements use the same background color and font family of the code blocks, this way it goes nicely inline with the current template.