Add initial postprocess unit test thingy.

recipe_engine/third_party/astunparse/__init__.py

Index: recipe_engine/third_party/astunparse/__init__.py
diff --git a/recipe_engine/third_party/astunparse/__init__.py b/recipe_engine/third_party/astunparse/__init__.py
new file mode 100644
index 0000000000000000000000000000000000000000..ddd64bed4c6ffb845df1084d5ccdb5fea483d7fa
--- /dev/null
+++ b/recipe_engine/third_party/astunparse/__init__.py
@@ -0,0 +1,20 @@
+# coding: utf-8
+from __future__ import absolute_import
+from six.moves import cStringIO
+from .unparser import Unparser
+from .printer import Printer
+
+
+__version__ = '1.4.0'
+
+
+def unparse(tree):
+    v = cStringIO()
+    Unparser(tree, file=v)
+    return v.getvalue()
+
+
+def dump(tree):
+    v = cStringIO()
+    Printer(file=v).visit(tree)
+    return v.getvalue()