add header extra args
add disqus identifier and url
add twitter, google plus, and facebook sharing
add twitter, google plus, and facebook sharing
add sharing info to README
add sharing info to README
add disqus_title
add more twitter options
add google plus options
merge with sharing branch
fix merge conflict
add default values to social media parameters
Merge branch 'sharing' into dev
add site search
fix merge conflicts
move head include into base so title block works correctly