Improvements by Hans Breuer:

	Improvements by Hans Breuer:

	* gdk/win32/gdkwindow.c (RegisterGdkClass): New function

	* gdk/win32/gdkwindow.c (gdk_window_new): Use it. Don't set the
	CS_?REDRAW flags as they cause lots of (late) redraws when "show
	window contents while dragging" is turned on. Allocate at least
	one unique class for every GdkWindowType. If support for single
	window-specific icons is ever needed (eg. Dialog specific), every
	such window should get its own class.