Khan/khan-exercises — pull request #26367 by mwittels (2012-07-17 23:39:12+00:00)
Title: Intro proofs

Added some bells and whistles, plus the hint system should (fingers crossed) not freak out.

http://sandcastle.khanacademy.org/media/castles/mwittels:introProofs/exercises/geometry_proofs_intro.html