When using the scroll wheel on the workspace indicators in single view,
make them use the same interpretation as the scrollbars: scrolling up
moves to the previous workspace, scrolling down to the next one.
https://bugzilla.gnome.org/show_bug.cgi?id=607824
Matching the 20091114 mockup, the default workspace view
is now a scrollable horizontal list, with a control to
switch between this and the previous grid view.
https://bugzilla.gnome.org/show_bug.cgi?id=593844