Change Discourse feed widget params

rssmikle_url: "http://discuss.okfn.org/category/open-knowledge-labs.rss" (specific labs rss feed instead of general OKFN rss feed)
rssmikle_title_bgcolor: "#7ab800" (to match site theme colors)
rssmikle_item_title_color: "#22998B"
responsive: "on" (to fill its container and make it work on mobile, too)
scrollstep: “6”

As referenced in #254