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).

Lib/importlib/NOTES

@@ -1,9 +1,16 @@
 to do
 /////
 
+* Document:
+
+    + The terms "importer", "finder", and "loader".
+    + machinery.BuiltinImporter.
+    + machinery.FrozenImporter.
+
 * Expose resolve_name().
 
 * Backport to Python 2.7.
+
     + import_module
     + resolve_name
 
@@ -11,9 +18,11 @@ to do
   that various implementations can just subclass as needed.
 
 * Expose built-in and frozen importers.
+
     + Make staticmethods so that class can be used directly.
 
 * Reorganize support code.
+
     + Separate general support code and importer-specific (e.g. source) support
       code.
         - Create support modules for each subdirectory (as needed).
@@ -22,12 +31,14 @@ to do
         - Use in source/test_load_module_mixed.
 
 * API simplification?
+
     + read_source -> get_data/source_path
     + read_bytecode -> get_data/bytecode_path
     + write_bytecode -> complete set of bytes for bytecode instead of
       individual arguments.
 
 * Implement PEP 302 protocol for loaders (should just be a matter of testing).
+
     + Built-in.
     + Frozen.
     + Extension.
@@ -36,39 +47,59 @@ to do
 * Create meta_path importer for sys.path.
 
 * OPTIMIZE!
+
   + Write benchmark suite.
   + Fast path common cases.
+
     - Absolute name from sys.path.
     - Relative name from sys.path.
 
 * Public API to expose (w/ docs!)
+
   + abc
+
       - Finder
+
         * find_module
+
       - Loader
+
         * load_module
+
       - ResourceLoader(Loader)
+
         * get_data
+
       - InspectLoader(Loader)
+
         * is_package
         * get_code
         * get_source
+
       - (?) SourceLoader(ResourceLoader)
+
         * source_path
         * bytecode_path
         * write_bytecode
+
   + util
+
       - get_module decorator (new name)
       - check_name decorator (new name)
-  + hooks (?)
+
+  + machinery
+
       - (?) Chained path hook/finder
       - BuiltinImporter
       - FrozenImporter
       - (?) FileFinder
       - Extensions importers
+
           * ExtensionFinder
           * (?) Loader
+
       - Source/bytecode importers
+
           * SourceFinder
           * (?) Loader