change slides the old desktop out and the new one in. Should not
be really technically different from the cube.
svn path=/branches/work/kwin_composite/; revision=629163
instances and keeping them around after the window is closed, create
class Deleted as a representation of a closed window.
svn path=/branches/work/kwin_composite/; revision=626356
besides drawing what should be drawn anyway, and there are
still some things missing like stacking order for override
redirect windows, but KWin is basically a compositing manager now.
svn path=/branches/work/kwin_composite/; revision=558168