A few arena-related fixes.

        * khtml/rendering/bidi.h: Don't define the operator new without the arena parameter.
	That way, we get a link failure if we use it by accident, rather than an assert at runtime.
	It would be even better to get a compile-time error, but I don't know how to make that happen.
        * khtml/rendering/render_layer.h: Ditto.
        * khtml/rendering/render_object.h: Ditto.
        * khtml/rendering/render_text.h: Ditto.

        * khtml/rendering/render_container.cpp:
        (RenderContainer::addChild): Create the RenderTable with the appropriate arena.
        (RenderContainer::insertPseudoChild): Create the RenderFlow objects with the appropriate arena.

        * khtml/rendering/render_text.cpp: (RenderText::deleteSlaves): Don't try to get the arena
	when there are no slaves. This can happen after the element is nil, and in that case we will
	do a nil-dereference.


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@2665 268f45cc-cd09-0410-ab3c-d52691b4dbfc