Add markup and copy for open-source community section

* Add basic style layout for the community section
* Add community icons
* Change layout of the community section
* Add button to section and clean up responsive style
* Uncomment social links in landing page
* Move stylesheets to modules folder
* Add global nav partial to index and featured social media links
* Remove community icons and restructure community section
* Add width to subtitle, call in locales, and reduce font size
* Reduce footer `p` size

![screen shot 2014-11-06 at 5 06 35 pm](https://cloud.githubusercontent.com/assets/5547897/4946866/64244224-661a-11e4-810d-00070b891be7.png)

I think we could work out the copy a little bit - but I think we could do that all at once when the landing page is closer to being finished.