def add nodechild, allows_children=true, &block
      # calling TreeNode.add
      $log.debug " XXX def add of DTM #{nodechild} to root "
      node = @root.add nodechild, allows_children, &block
      if @handler # only if someone is listening, won't fire when being prepared
        tme = TreeModelEvent.new(row, row,:ALL_COLUMNS,  self, :INSERT)
        fire_handler :TREE_MODEL_EVENT, tme
      end
      #return @root
      return node
    end
def add nodechild, allows_children=true, &block
      # calling TreeNode.add
      $log.debug " XXX def add of DTM #{nodechild} to root "
      node = @root.add nodechild, allows_children, &block
      if @handler # only if someone is listening, won't fire when being prepared
        tme = TreeModelEvent.new(row, row,:ALL_COLUMNS,  self, :INSERT)
        fire_handler :TREE_MODEL_EVENT, tme
      end
      #return @root
      return node
    end
add a node to root passing a block optionally
 @param [String, TreeNode, Array, Hash] node/s to add
 @param [Boolean] allow children to be added
 @see TreeNode.add
 @return [TreeNode] node just added to root (NOT self)