This modifies all the contrib modules to work (so far as I know) with the
new contrib layout. The exception is the LayoutHooks module, which isn't
used. It exports an API that is inherently unsafe, so far as I can tell
(and always has been).
It's unclear to me what SimpleStacking is supposed to accomplish, so I'm just
going to note that it doesn't work with Xinerama. (Due to assuming that the
current workspace is the one being laid out)
WARNING! This change will break existing Tabbed configurations. The
problem is that there is no way within a Layout's "doLayout" to safely
modify the layout itself. This makes LayoutHooks fragile, and more to the
point, makes SimpleStacking fragile, so we can't safely define a
tabbed' = simpleStacking . tabbed
A workaround would have been to duplicate the tabbed code, but I'd rather
leave the ugliness and get this fixed.
