file logging for errors
fixing some formatting
chmod 777
AWS S3 support for activity image upload
upgraded bootstrap to 3.0.3
removed the modal for image previews, added recent activities to challenges.
div around disqus link
sometimes I suck.
when a user tries to access a challenge that does not exist, redirect them to the challenges list
Merge branch 'refs/heads/teams' into python-social-auth

Conflicts:
	requirements.pip
switched from django-social-auth to python-social-auth.  better handling of authentication errors and improved error pages.