Merge pull request #2371 from Stanford-Online/jbau-wallawalla-fall2012

Jbau wallawalla fall2012
Merge pull request #2369 from Stanford-Online/jbau-s3-exercise-fix

change order of statements to fix s3 exercise save
landing page: add edX merger at the top (#2505)
Merge pull request #2514 from Stanford-Online/sef-2505-edx-readme-homepage-fall2012

edX on landing page -- FALL2012 MASTER
Merge branch 'fall2012-master' of github.com:Stanford-Online/class2go into fall2012-production