* X11Structs.cs: Add a few ToString() overrides.
* XplatUIX11.cs: Added GetTopLevelWindowLocation to try to calculate
the window location in a window-manager independent way. Reworked
FrameExtents, it now actually works. Reworked AddConfigureNotify
and ReparentNotify handling to use GetTopLevelWindowLocation
instead of the earlier, more hacky solution. Reworked SetWMStyles,
hopefully for the better: we now set _NET_WM_WINDOW_TYPE* for all
windows, DIALOG for modal windows, UTILITY for toolboxes and NORMAL
for all other windows (fixes #81281 part 1), a toolwindow is hidden
from the taskbar if it has a parent (fixes #81281 part 2 for kwin),
and generally refactored to do as few calculations as possible
inside the lock.
svn path=/trunk/mcs/; revision=75578