add Heroku SSH setup
add heroku ssh images
Add for section to data structures
Merge remote-tracking branch 'upstream/master'
Added for to slides
Merge pull request #56 from mrwhelan/master

Fixed issue #21 by adding to OS X install instructions
Merge remote-tracking branch 'upstream/master'
Fix web section typos to fix Issue #43
Add clarifications to web section to fix Issue #44
Fix formatting problem in web section
Merge pull request #57 from bridgethillyer/master

Add for section to data structures
Fix font errors