gmoccapy: fix wrong states of spindle button images after program abort

When a program with spindle on is aborted (assuming spindle off before program start), the images of the spindle buttons get a wrong state: the CSS property "-gtk-icon-effect" is set to "dim" which should be only set when they are disabled.
Toggling the sensitive property twice corrects this wrong CSS property.

src/emc/usr_intf/gmoccapy/gmoccapy.py

@@ -4002,21 +4002,30 @@ def on_rbt_forward_clicked(self, widget, data=None):
             widget.set_image(self.widgets.img_spindle_forward_on)
             self._set_spindle("forward")
         else:
-            self.widgets.rbt_forward.set_image(self.widgets.img_spindle_forward)
+            widget.set_image(self.widgets.img_spindle_forward)
+        # Toggling the sensitive property is important here! See the commit description.
+        widget.set_sensitive(not widget.get_sensitive())
+        widget.set_sensitive(not widget.get_sensitive())
 
     def on_rbt_reverse_clicked(self, widget, data=None):
         if widget.get_active():
             widget.set_image(self.widgets.img_spindle_reverse_on)
             self._set_spindle("reverse")
         else:
             widget.set_image(self.widgets.img_spindle_reverse)
+        # Toggling the sensitive property is important here! See the commit description.
+        widget.set_sensitive(not widget.get_sensitive())
+        widget.set_sensitive(not widget.get_sensitive())
 
     def on_rbt_stop_clicked(self, widget, data=None):
         if widget.get_active():
             widget.set_image(self.widgets.img_spindle_stop_on)
             self._set_spindle("stop")
         else:
-            self.widgets.rbt_stop.set_image(self.widgets.img_spindle_stop)
+            widget.set_image(self.widgets.img_spindle_stop)
+        # Toggling the sensitive property is important here! See the commit description.
+        widget.set_sensitive(not widget.get_sensitive())
+        widget.set_sensitive(not widget.get_sensitive())
 
     def _set_spindle(self, command):
         # if we are in estop state, we will have to leave here, otherwise
@@ -4029,18 +4038,6 @@ def _set_spindle(self, command):
         # be set to the commanded value due to the next code part
         if self.stat.task_mode != linuxcnc.MODE_MANUAL:
             if self.stat.interp_state == linuxcnc.INTERP_READING or self.stat.interp_state == linuxcnc.INTERP_WAITING:
-                if self.stat.spindle[0]['direction'] > 0:
-                    self.widgets.rbt_forward.set_sensitive(False)
-                    self.widgets.rbt_reverse.set_sensitive(True)
-                    self.widgets.rbt_stop.set_sensitive(True)
-                elif self.stat.spindle[0]['direction'] < 0:
-                    self.widgets.rbt_forward.set_sensitive(True)
-                    self.widgets.rbt_reverse.set_sensitive(False)
-                    self.widgets.rbt_stop.set_sensitive(True)
-                else:
-                    self.widgets.rbt_forward.set_sensitive(True)
-                    self.widgets.rbt_reverse.set_sensitive(True)
-                    self.widgets.rbt_stop.set_sensitive(False)
                 return
 
         rpm = self._check_spindle_range()