FIX: Loading file in 3D main view and 3D detail view

It's a regression in my recent commit.
Used _ for a dummy int variable, and _('localization')  broke.
Added logging where the exception was
silently ignored

printrun/gl/libtatlin/actors.py

@@ -591,7 +591,7 @@ def load_data(self, model_data, callback=None):
                         new_vertices_count = new_vertices_len//coordspervertex
                         # settings support alpha (transperancy), but it is ignored here
                         gline_color = self.movement_color(gline)[:buffered_color_len]
-                        for _ in range(new_vertices_count):
+                        for vi in range(new_vertices_count):
                             colors[color_k:color_k+buffered_color_len] = gline_color
                             color_k += buffered_color_len
 

printrun/pronterface.py

@@ -1635,6 +1635,7 @@ def loadviz(self, gcode = None):
             # finalized model from the main visualization
             self.gwindow.p.addfile(gcode)
         except:
+            logging.error(traceback.format_exc())
             wx.CallAfter(self.gviz.Refresh)
 
     #  --------------------------------------------------------------