Revert "Revert "add track function""

This reverts commit 4a522dd8b5e82a2c69cdd87f24d0421ccafc5535.
Revert "Revert "test""

This reverts commit fec7299a32eeb11dc5a12991fb0251daf24af276.
Revert "test"

This reverts commit 21c3757b88437477139f40b4443696dbc8b153f0.
fix post 2012-10-21 under new jekyll