SAGE Knowledge translator (new)

Sample URL:
http://knowledge.sagepub.com/view/10-winning-strategies-for-leaders-in-the-classroom/SAGE.xml?rskey=yrcpOl&row=1
For URL, maybe use the actual URL. This is a bit redundant with the DOI field, not sure if the DOI actually leads to the same place. It's fairly trivial if you make `getItem` take a second argument, which would be the URL passed from `ZU.processDocuments`