def prepend_child(node)
      raise "argument to << must be a String or Ox::Node." unless node.is_a?(String) or node.is_a?(Node)
      @nodes = [] if !instance_variable_defined?(:@nodes) or @nodes.nil?
      @nodes.unshift(node)
      self
    end
def prepend_child(node)
      raise "argument to << must be a String or Ox::Node." unless node.is_a?(String) or node.is_a?(Node)
      @nodes = [] if !instance_variable_defined?(:@nodes) or @nodes.nil?
      @nodes.unshift(node)
      self
    end
Prepend a Node to the Element's nodes array. Returns the element itself
 so multiple appends can be chained together.
 - +node+ [Node] Node to prepend to the nodes array