function abs_end(){
		$Node = $this;
		while( $Child = end( $Node->children ) ){
			$Node = $Child;
		}
		return $Node;
	}
function abs_end(){
		$Node = $this;
		while( $Child = end( $Node->children ) ){
			$Node = $Child;
		}
		return $Node;
	}
function abs_end ( ) { $ Node = $ this ; while ( $ Child = end ( $ Node -> children ) ) { $ Node = $ Child ; } return $ Node ; }
recursively get last element in entire tree
@return ParseNode
recursively get last element in entire tree