Auto tuning

Reimplement auto based on python-livereload as explained in serialized.net for #559

Improvements:

* Offers a auto-reloading browser window, which is wicked cool
* Detects changes in conf.py

Not so much:

* Adds a dependecy (but it's small, and really, I could just embed it)
* Creates a file, called Guardfile, which is not great UX
* ~~Doesn't detect file addition, but that seems to me a bug in livereload and have reported it~~ Fixed in livereload master