Change so jekyll can be run on Windows behind our firewall

@allisoncorey, I wrote up the steps that I took [here](http://redmine.virtualworldframework.com/projects/vwf/wiki/Run_Jekyll_on_Windows)
When you get a chance, can you see if you can set jekyll up to run on Windows, too?

@jessmartin, I'm leaning on you to tell me if this still works on your Mac.  Also, if you have any pointers for Gemfile / Gemfile.lock tidiness.

Let me know if you guys think this is ready to merge.