Patternfly pull request

Hi, I made a pull request for the port to Patternfly: https://github.com/cockpit-project/cockpit/pull/223 It's a big change, and frankly, my eyes glaze over when I try to review it. I guess I need some distance. :-) So, please everyone have a look. Please install the branch and play around with it. Let's try to get this in by the end of the week or so, so that we can re-open src/web on master.