Include json2.js to fix "Error: 'serializer' is null or not an object"
error on IE8.

See comments in this post:

http://easyxdm.net/wp/2011/04/13/microsoft-security-bulletin-ms11-018/
Change json2.js to minified version.
Merge pull request #25 from scraperwiki/20131210-javascript-fix-for-ie-8

20131210 javascript fix for ie 8