the python-prefered mode.
This is available so that the scripting functions know whether on not to put themselves onto in as menu items.
If you consider using this, consider in preference use_gui_qm == 2, which is used elsewhere to stop python functions adding to the gui, when guile-gtk functions have alread done so. We should clean up this (rather obscure) interface at some stage.
return 1 for python is prefered, 0 for not.