Multiple window operations

[Gregory Merchan <merchan phys lsu edu>]

Looking through the still out-of-date wm-spec at freedesktop.org,
I see no messages for multiple window operations. These are those that
require two or more windows such as tiling and cascading.

While both of these could be done by computation on the requestor side
followed by _NET_WM_MOVERESIZE messages, it would seem better to leave
the computations to the window manager.


Cheers,
Greg Merchan