Add importlib.machinery with its first tenants, BuitinImporter and
FrozenImporter. Docs forthcoming.

I plan on all finders and loaders (and most likely hooks) to live
in imoprtlib.machinery. Utility stuff will end up in importlib.util.
Higher-level API stuff will stay on imoprtlib directly (e.g. import_module).
diff --git a/Lib/importlib/machinery.py b/Lib/importlib/machinery.py
new file mode 100644
index 0000000..40d39f4
--- /dev/null
+++ b/Lib/importlib/machinery.py
@@ -0,0 +1,4 @@
+"""The machinery of importlib: finders, loaders, hooks, etc."""
+
+from ._bootstrap import BuiltinImporter
+from ._bootstrap import FrozenImporter