Added example thread cutter to default library

src/Mod/Path/Tools/Bit/5mm-thread-cutter.fctb

@@ -0,0 +1,14 @@
+{
+  "version": 2,
+  "name": "3mm-thread-cutter",
+  "shape": "thread-mill.fcstd",
+  "parameter": {
+    "Crest": "0.10 mm",
+    "Diameter": "5.00 mm",
+    "Length": "50.00 mm",
+    "NeckDiameter": "3.00 mm",
+    "NeckHeight": "20.00 mm",
+    "ShankDiameter": "5.00 mm"
+  },
+  "attribute": {}
+}

src/Mod/Path/Tools/Library/Default.fctl

@@ -31,6 +31,10 @@
     {
       "nr": 8,
       "path": "probe.fctb"
+    },
+    {
+      "nr": 9,
+      "path": "5mm-thread-cutter.fctb"
     }
   ],
   "version": 1