def delete_all( xpath )
      rv = []
      XPath::each( @element, xpath) {|element| 
        rv << element if element.kind_of? Element
      }
      rv.each do |element|
        @element.delete element
        element.remove
      end
      return rv
    end
def delete_all( xpath )
      rv = []
      XPath::each( @element, xpath) {|element| 
        rv << element if element.kind_of? Element
      }
      rv.each do |element|
        @element.delete element
        element.remove
      end
      return rv
    end
Removes multiple elements.  Filters for Element children, regardless of
 XPath matching.
 xpath:: all elements matching this String path are removed.
 Returns:: an Array of Elements that have been removed
  doc = Document.new '<a><c/><c/><c/><c/></a>'
  deleted = doc.elements.delete_all 'a/c' #-> [<c/>, <c/>, <c/>, <c/>]