Force hyphenation of {{ category }} links

Hey Alex,

Love the theme! I did, however, notice that my category links were broken. I tend to use long category names with spaces in them, so just having unprocessed {{ category }} in the <a> tags was no good. 

How about forcing hyphenation like this? It solved the issue for [my site](http://iamscottrogers.com), at least. You can see it in action there.


Thanks!

Scott