This renderer simply calles the methods of a number of other Renderes sequentially. Only
Renderer.Type.HEAD renderers can be chained, because they don't have to produce a well defined
block.
author: Michiel Meeuwissen version: $Id: ChainedRenderer.java,v 1.4 2008/02/03 17:33:56 nklasens Exp $ since: MMBase-1.9