- fixed the crashing so the layout tests work

        * khtml/rendering/render_layer.h: Add a node pointer result.
        * khtml/rendering/render_layer.cpp: (RenderLayer::elementList):
	Return the node pointer so we can destroy it when done with it.

        * khtml/rendering/render_object.h: Make renderArena() const.
        * khtml/rendering/render_object.cpp: (RenderObject::renderArena): Make it const.

        * kwq/KWQRenderTreeDebug.cpp: (writeLayers): Free the Z layer list when done.
	Without this things just crashed.


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@3353 268f45cc-cd09-0410-ab3c-d52691b4dbfc