fix "nothing?callback=onJSONP_Data" 404 (Not Found) error

[gotjoshua]

When trying to update recline and timemapper to the most recent TimelineJS, i was getting a 404 (Not Found) error relating to a final getJSON call to "nothing?callback=onJSONP_Data"
Investigation showed that the data was already received, but not being added to the config.source, which resulted in a call to "nothing" the default source on the config object.

additionally I changed to the ajax call rather than getJSON based on the advice of the article that I cited in the comment:
http://stackoverflow.com/questions/1002367/jquery-ajax-jsonp-ignores-a-timeout-and-doesnt-fire-the-error-event

This seemed to work inside timemapper, but broke the timelineJS test:
http://recline.1zm.in/vendor/TimelineJS2/tests/test_extra_html.html

So i rolled it back to still use getJSON... I left the comment in there to start a discussion... what are the advantages of getJSON? do you agree in general with the advice from Husky on that stackoverflow link?

cheers,
gotjoshua