Bug fix & README improvements

Hi there @moviepilot,

Thanks a lot for writing this, has saved me a lot of time! :smile:

In this PR I've fixed a bug was preventing 301 redirects from working correctly when the request is pulled from cache. Also, I've updated the `README.md` so it includes steps on compiling the config with CoffeeScript.

Side note: when I build `src/seoserver.coffee` with coffee it generates a pretty large diff for `lib/seoserver.js`, so I can only assume that I'm running a different version of CoffeeScript than you. I've updated the js manually at this stage. If you want to compile it yourself, let me know and I'll remove my manual update.

Lex