Add vpython support to Python recipe module.

recipe_modules/python/example.expected/basic.json

 [
   {
     "cmd": [
       "python",
       "-u",
       "import sys; sys.exit(0)"
     ],
     "name": "success",
     "~followup_annotations": [
       "@@@STEP_LOG_LINE@success@This step is a success@@@",
@@ skipping 31 matching lines @@
       "-u",
       "print \"Hello World!\""
     ],
     "name": "inline",
     "~followup_annotations": [
       "@@@STEP_LOG_LINE@python.inline@print \"Hello World!\"@@@",
       "@@@STEP_LOG_END@python.inline@@@"
     ]
   },
   {
+    "cmd": [
+      "vpython",
+      "-u",
+      "RECIPE[recipe_engine::python:example].resources/test.py"
+    ],
+    "name": "run vpython.script"
+  },
+  {
+    "cmd": [
+      "vpython",
+      "-spec",
+      "RECIPE[recipe_engine::python:example].resources/test.vpython",
+      "-u",
+      "RECIPE[recipe_engine::python:example].resources/test.py",
+      "--verify"
+    ],
+    "name": "run vpython.spec"
+  },
+  {
     "name": "$result",
     "recipe_result": null,
     "status_code": 0
   }
 ]