stepconf: look for linuxcnc-wizard image in the correct dirs

A cut-n-paste error ('wizard' vs 'linuxcncicon' prevented stepconf
from finding the linuxcnc-wizard image now that stepconf's using its
own datadir.

Also, since i'm already here, clean up the wizard image search paths
a little.
task state: teach linuxcnctop.py, emcmodule.cc about WAITING_FOR_SPINDLE_ORIENTED