- minor UI changes for Gerber UI

- ~~after an object move, the apertures plotted shapes are deleted from canvas and the 'mark all' button is deselected~~
- after move tool action or any other transform (rotate, skew, scale, mirror, offset), the plotted apertures are kept plotted.
- changing units now will convert all the default values from one unit type to another
- prettified the selection shape and the moving shape
- initial work in object hovering shape

flatcamTools/ToolNonCopperClear.py

@@ -345,13 +345,13 @@ class NonCopperClear(FlatCAMTool, Gerber):
         self.obj_name = ""
         self.ncc_obj = None
         self.tool_type_item_options = ["C1", "C2", "C3", "C4", "B", "V"]
-        self.units = self.app.ui.general_options_form.general_app_group.units_radio.get_value().upper()
+        self.units = self.app.ui.general_defaults_form.general_app_group.units_radio.get_value().upper()
 
     def build_ui(self):
         self.ui_disconnect()
 
         # updated units
-        self.units = self.app.ui.general_options_form.general_app_group.units_radio.get_value().upper()
+        self.units = self.app.ui.general_defaults_form.general_app_group.units_radio.get_value().upper()
 
         if self.units == "IN":
             self.addtool_entry.set_value(0.039)