changes to mongo_formatter

Output Tabari formatted 'eventrecords...txt' from 'scraper_results..txt' where key for each story is the url for the story backwords: e.g., for story http://stream.wsj.com/story/latest-headlines/SS-2-63399/SS-2-444966/

140203 /669444-2-SS/99336-2-SS/senildaeh-tsetal/yrots/moc.jsw.maerts//:ptth
Gov. Chris Christie, in a live radio appearance on Monday, denied any knowledge of or planning 
role in the lane closures at the George Washington Bridge last year, his first public remarks 
in nearly a month on a matter that threatens his political ambitions.