Update Batman Website

I've tried to pull together the brochure update we did into something shippable. It would be great if you guys could run this `jekyll serve`, dig around and let me know what you think. I need to finish some links on the downloads page but am blocked by the need to launch Batman 0.15, my large update to batman-rails and some work to provide a simple ruby web server to serve a batman project.

I've removed some examples because they were out of date and not maintained, and added lots of external links. Please suggest any additional links you know of.

@nickjs @hornairs @kristianpd @jamesmacaulay 
/cc @benwatts @Healthcare