Added code to include source files from 'build_clib' command to default file
list -- currently this won't work, since 'build_clib' doesn't have a
'get_source_files()' method!
provided by Distribution.
Cosmetic and error message tweaks.
Simplified 'make_release_tree()':
* extracted 'distutils.util.create_tree()'
* don't have to do hard-linking ourselves -- it's now handled by
'distutils.util.copy_file()' (although the detection of
whether hard linking is available still needs to be factored out)
Removed 'make_tarball()' and 'make_zipfile()' entirely -- their role
is now amply filled by 'distutils.util.make_archive()'.
Simplified 'make_distribution()':
* use Distribution's new 'get_full_name()' method
* use 'make_archive()' instead of if/elif/.../else on the archive format
old 'dist' command, but the code for dealing with manifests is completely
redone -- and renaming the command to 'sdist' is more symmetric with the
soon-to-exist 'bdist' command.