When filmmaker Peter Jackson announced J.R.R. Tolkien’s slim novel The Hobbit would be three movies instead of two (or even one), even more eyebrows were raised than when it was announced Guillermo del Toro would take over as director.  Del Torro would ultimately have to bow out, but all three movies are getting made, and Jackson explains why on the discs of The Hobbit: An Unexpected Journey Extended Edition. The theatrical cut was about ten minutes shy of three hours, and the extended cut adds about thirteen minutes. But the meat of this special edition…