Fix broken history links on history page
Bump version to 7.3.32
Bump version to 7.3.32-dev
Add Twitter link in footer
Bump version to 7.3.33
Bump version to 7.3.33-dev
Merge branch 'master' into username

Conflicts:
	www/%username/history/index.html
	www/assets/%version/gittip.css
Fix some tests re: participant model; #287