[#306] Fix error where icon passed to qs in links
Fix IRC channel link in README

Link to #ckan channel on webchat.freenode.net
Update issue tracker link in README
Update contributing link in README
Merge pull request #306 from okfn/306-header-link-icon-qs

?icon=None in links that use h.url_for with the icon attribute
Merge branch 'master' into release-v2.0