code: function getPathAncestors(filename){
      var tree = filename.split('/');
      tree.pop(); // remove last
      
      var treePath = [];
      for(var i=0;i<tree.length;i++){
          treePath.push(createId(tree, i));
      }
      
      function createId(tree, count){
          var id = '';
          for(var i=0;i<=count;i++){
              id += (i>0 ? '/' : '') + tree[i];
          }
          return id;
      }
      
      return treePath;
  }
docs: helper - create ancestors list from path
  @param {String} filename
  @returns {Array}  ancestors list