Add some real content to the gh-pages site

I decided that we needed a good homepage for ev3dev. The current landing for ev3dev.org is... underwhelming for someone looking at the project for the first time, and the readme in its entirety probably isn't what people want to see if they are sharing the project or just want an overview. I decided to write some content with one of the GitHub Pages themes (included in this pull request, as well as currently hosted in [my fork](http://wasabifan.github.io/ev3dev/)).

Notable features:
- A logo using a link to the org logo for ev3dev, so if we want a different logo it's easily changeable from GitHub itself
- I included all the content that someone would want if they wanted an overview of the whole project. This includes the included languages and wrappers, form factor, features, and some assorted FAQ

I really just wanted to take all the information and create an inviting page for people to see. I was thinking that it could be a good page to put up on/as ev3dev.org. We could also put it up (or move it over) as the ev3dev organization page, if we decide to move all the repos over there.