Fix social buttons problem in Firefox.

- This problem happens in Firefox 32 for Mac.
Adding section of Featured Elements.
Merge branch 'gh-pages' of github.com:obetomuniz/customelements.io into gh-pages

* 'gh-pages' of github.com:obetomuniz/customelements.io:
  Fix social buttons problem in Firefox.

Conflicts:
	css/main.css