#202 Jstor fetcher doesn't work anymore

[Nicolas Brouard]

Hi,

The former query to Jstor via BibsonomyScraper:
http://www.jstor.org/action/exportSingleCitation?singleCitation=true&suffix=1529265
doesn't work anymore and you can't fetch Jstor with Jabref anymore.

But a query with a standard prefix 10.2307 for Jstor seems to work:
http://www.jstor.org/action/exportSingleCitation?singleCitation=true&doi=10.2307/1529265

Therefore, I am proposing this patch.