Polymer/core-ajax — pull request #25 by benzen (2014-09-12 12:07:25+00:00)
Title: Add support complexe object into queryParams

convert each value candidate to string params into a json string before
go into encoreURIComponent

Used JSON.stringify, which according to http://caniuse.com/#search=JSON
is available in every browser without restriction since IE9

Added test for that, but can't run them since there is missing parts for
running them from the sources