These routines interact with a window manager
to set the properties of the window running the current program.
They substitute for interacting directly with the Plan 9
Drawresizewindow requests that the programs window be resized to have the
width and height of the rectangle
r. Only the width and height
are important; the offset is ignored.
Drawsetlabel requests that the programs window title be set to
Drawtopwindow requests that the programs window be moved
above all other windows and given the input focus.