Missed these files in the last commit ..

Also meant to mention, on the todo: show the confirmation before closing the file selector, 
rather than afterwards where it's inconvenient and easy to miss...

release/scripts/io/export_obj.py

@@ -897,7 +897,8 @@ class ExportOBJ(bpy.types.Operator):
     # to the class instance from the operator settings before calling.
 
     path = StringProperty(name="File Path", description="File path used for exporting the OBJ file", maxlen= 1024, default= "")
-
+    check_existing = BoolProperty(name="Check Existing", description="Check and warn on overwriting existing files", default=True, hidden=True)
+    
     # context group
     use_selection = BoolProperty(name="Selection Only", description="", default= False)
     use_all_scenes = BoolProperty(name="All Scenes", description="", default= False)