- converted from Python2 code to Python3 code

- in camlib.py, CNCJob class -> generate_from_excellon_by_tool() was
failing in the line to sort the tools due of been unable to compare
between dict's. I replaced that section.

ObjectCollection.py

@@ -39,10 +39,10 @@ class ObjectCollection():
     }
 
     icon_files = {
-        "gerber": "share:flatcam_icon16.png",
-        "excellon": "share:drill16.png",
-        "cncjob": "share:cnc16.png",
-        "geometry": "share:geometry16.png"
+        "gerber": "share/flatcam_icon16.png",
+        "excellon": "share/drill16.png",
+        "cncjob": "share/cnc16.png",
+        "geometry": "share/geometry16.png"
     }
 
     def __init__(self, parent=None):
@@ -102,7 +102,7 @@ class ObjectCollection():
 
     def print_list(self):
         for obj in self.object_list:
-            print obj
+            print(obj)
 
     def on_mouse_down(self, event):
         FlatCAMApp.App.log.debug("Mouse button pressed on list")