When you try to append a plot to another plot that has been redirected to a
gki file, PyRAF hangs.
--> prow dev$pix 256 >G test.gki
--> prow dev$pix 250 append+ >>G test.gki
(PyRAF hangs, must be ^C'd)
This arises because the graphics kernel that handles graphics redirection does not
handle WCS gets and sets. PyRAF hangs because the prow task is waiting for PyRAF
to send it some WCS information, and PyRAF doesn't have any to send.
The solution is to add control_getwcs and control_setwcs methods to the GkiRedirection?
class. When the WCS is set using control_setwcs, it needs to be saved so that the next
plot can use it. It is saved in the wcs attribute of the GkiController? object that is
instantiated when the gki module is imported (and is persistent over a session).
The IrafExecute? function needs to copy over this wcs to the GkiRedirection? object that is
instantiated from scratch every time PyRAF detects that it has to redirect a plot to a
gki file.
