code: function relativeTOC(file, parent) {
          _.each(parent.children, function(child) {
            if(child.relative) {
              var href = "";
              if(config.format != "pdf") {
                var relativeFolder = path.relative(path.dirname(file.relative), path.dirname(child.relative));
                href = path.join(relativeFolder, path.basename(child.relative))
              }
              if(child.id) {
                href += "#" + child.id;
              }
              child.href = href;
            }
            if(child.children) {
              child = relativeTOC(file, child);
            }
          });
          return parent;
        }
docs: a function to turn a toc tree into relative URL's for a specific file.