VS: Add NASM fwin/felf switches

The generated NASM file from the xml does not contain the fwin/felf
switches that don't seem to directly exist in the xml file.

Templates/MSBuild/FlagTables/v10_NASM.json

 [
+  {
+    "name": "Outputswitch",
+    "switch": "fwin",
+    "comment": "Object File win32",
+    "value": "0",
+    "flags": []
+  },
   {
     "name": "Outputswitch",
     "switch": "fwin32",
@@ -13,6 +20,13 @@
     "value": "1",
     "flags": []
   },
+  {
+    "name": "Outputswitch",
+    "switch": "felf",
+    "comment": "ELF32 (i386) object files (e.g. Linux)",
+    "value": "2",
+    "flags": []
+  },
   {
     "name": "Outputswitch",
     "switch": "felf32",