tools to automatically update github pages

@lileicc 

Docs now live at http://bayesianlogic.github.io/.

To update the docs, you can use "sbt/sbt ghpages".

Note that the bayesianlogic.github.io repo has to be cloned in the same parent dir as the blog repo, e.g. `~/blog` and `~/bayesianlogic.github.io`.