even if package_dir is empty.

This needs to be backported.  I'm too tired tonight.  It would be great
if someone backports this if the buildbots are ok with it.  Otherwise,
I will try to get to it tomorrow.

immediately (since None is not a sequence you can iterate over).

This is basically the support for package data from Phillip Eby's
setuptools package.  I've changed it only to fit it into the core
implementation rather than to live in subclasses, and added
documentation.

    suggested by PEP 291.

This is a conservative version of SF patch 504889.  It uses the log
module instead of calling print in various places, and it ignores the
verbose argument passed to many functions and set as an attribute on
some objects.  Instead, it uses the verbosity set on the logger via
the command line.

The log module is now preferred over announce() and warn() methods
that exist only for backwards compatibility.

XXX This checkin changes a lot of modules that have no test suite and
aren't exercised by the Python build process.  It will need
substantial testing.

local conventions before being used by build_py.

Fixes SF bug #509288, probably a candidate for 2.2.1

by default (since compiling at install time works just fine).  Details:
  - added 'compile' and 'optimize' options
  - added 'byte_compile()' method
  - changed 'get_outputs()' so it includes bytecode files
A lot of the code added is very similar to code in install_lib.py;
would be nice to factor it out further.

on the module file -- could be useful for subclasses overriding it.

Changed 'core.setup()' so it sets them to reasonable defaults.
Tweaked how the "usage" string is generated: 'core' now provides
  'gen_usage()', which is used instead of 'USAGE'.
Modified "build_py" and "sdist" commands to refer to
  'self.distribution.script_name' rather than 'sys.argv[0]'.

represents packages as strings, not tuples.  This allowed a simplification
in 'get_package_dir()', too -- can now assume that 'package' is a string.

(and in order to generate a more sensible error message cleanly).

attempt to verify the bold assertions in the documentation):
  * entries for the "root package" in 'package_dir' didn't work --
    fixed by improving the fall-through code in 'get_package_dir()'
  * __init__.py files weren't installed when modules-in-packages
    were listed individually (ie. in 'py_modules' in the setup script);
    fixed by making 'check_package()' return the name of the __init__
    file if it exists, and making 'find_modules()' add an entry to
    the module list for __init__ if applicable

timestamps), so every build_* command has 'self.force', which follows the
'build' command if not set by the user.

A host of improvements in preparation for the 'bdist' command:
  - added 'get_outputs()' method (all the other improvements were to support
    this addition)
  - made 'find_package_modules()' and 'find_modules()' return similar
    values (list of (package, module, module_filename) tuples)
  - factored 'find_all_modules()' out of 'get_source_files()' (needed
    by 'get_outputs()')
  - factored 'get_module_outfile()' out of 'build_module()' (also needed
    by 'get_outputs()')
  - various little tweaks, improvements, comment/doc updates

'set_final_options()' to 'finalize_options()'.

command itself: no more of this "FooBar class for foo_bar command"
silliness.