- modified behind the scene the UI for Tool Subtract

- modified some strings and updated the translation strings
- in NCC Tool added a check for the validity of the used tools; its only informative
- in NCC Tool done some refactoring

defaults.py

@@ -461,26 +461,27 @@ class FlatCAMDefaults:
         "tools_drill_area_overz": 1.0,
 
         # NCC Tool
-        "tools_ncctools": "1.0, 0.5",
-        "tools_nccorder": 'rev',
-        "tools_nccoperation": 'clear',
-        "tools_nccoverlap": 40,
-        "tools_nccmargin": 1.0,
-        "tools_nccmethod": _("Seed"),
-        "tools_nccconnect": True,
-        "tools_ncccontour": True,
-        "tools_nccrest": False,
+        "tools_ncc_tools": "1.0, 0.5",
+        "tools_ncc_order": 'rev',
+        "tools_ncc_operation": 'clear',
+        "tools_ncc_overlap": 40,
+        "tools_ncc_margin": 1.0,
+        "tools_ncc_method": _("Seed"),
+        "tools_ncc_connect": True,
+        "tools_ncc_contour": True,
+        "tools_ncc_rest": False,
         "tools_ncc_offset_choice": False,
         "tools_ncc_offset_value": 0.0000,
-        "tools_nccref": _('Itself'),
+        "tools_ncc_ref": _('Itself'),
         "tools_ncc_area_shape": "square",
-        "tools_nccmilling_type": 'cl',
-        "tools_ncctool_type": 'C1',
-        "tools_ncccutz": -0.05,
-        "tools_ncctipdia": 0.1,
-        "tools_ncctipangle": 30,
-        "tools_nccnewdia": 0.1,
+        "tools_ncc_milling_type": 'cl',
+        "tools_ncc_tool_type": 'C1',
+        "tools_ncc_cutz": -0.05,
+        "tools_ncc_tipdia": 0.1,
+        "tools_ncc_tipangle": 30,
+        "tools_ncc_newdia": 0.1,
         "tools_ncc_plotting": 'normal',
+        "tools_ncc_check_valid": True,
 
         # Cutout Tool
         "tools_cutout_tooldia": 2.4,