Add initial implementation of importlib. See the NOTES files for what is

planned for the package.

There are no docs yet, but they are coming once the API for the first new
function, importlib.import_module() is finalized.

Lib/importlib/test/extension/__init__.py

@@ -0,0 +1,13 @@
+import importlib.test
+import os.path
+import unittest
+
+
+def test_suite():
+    directory = os.path.dirname(__file__)
+    return importlib.test.test_suite('importlib.test.extension', directory)
+
+
+if __name__ == '__main__':
+    from test.support import run_unittest
+    run_unittest(test_suite())