Refactor mod/lock.
feat(README): add directory TTL documentation
Merge pull request #384 from benbjohnson/refactor-mod-lock

Refactor mod/lock.
fix(dispatch) should call e.Index()
Merge pull request #393 from xiangli-cmu/fix_index

fix(dispatch) should call e.Index()
fix(store.go) report node.path
Merge pull request #394 from xiangli-cmu/fix_error_msg

fix(store.go) report node.path
Merge pull request #389 from philips/document-ttl-directories

feat(README): add directory TTL documentation