'run_command()' to refer to it before attempting to run a command --
  that way, command classes can freely invoke other commands without fear
  of duplicate execution.
Beefed up some comments and docstrings.

Amos Latteier <amos@aracnet.com>).

meaningful return values: respectively, whether the copy was done, and
the list of files that were copied.  This meant some trivial changes in
core.py as well: the Command methods that mirror 'copy_file()' and
'copy_tree()' have to pass on their return values.

of the 'install_py' command rather than 'build_py'.  Obviously, this
meant that the 'build_py' and 'install_py' modules had to change; less
obviously, so did 'install' and 'build', since these higher-level
commands must make options available to control the lower-level
commands, and some compilation-related options had to migrate with the
code.

and dry-run flags consistently painless): 'execute()', 'mkpath()',
'copy_file()', 'copy_tree()', 'make_file()', and stub for 'make_files()'
(not sure yet if it's useful).

  that wrap them in the Command class).
Fixed 'copy_file()' to use '_copy_file_contents()', not 'copyfile()'
  from shutil module -- no reference to shutil anymore.
Added "not copying" announcement in 'copy_file()'.
Wee comment fix.

and 'make_file()'-- that way, the verbose and dry-run flags are
handled for free.

works on non-seekable file-like objects, such as URLs.  (Oops.)

ProcessHierarchy's changes to support reading from a remote URL in
ProcessDatabase).

a much less formalistic way.  Just keeping this around for possible
future reference.

files with (optional) comment stripping, blank line skipping, whitespace
removal, and line joining with trailing backslashes.

	installations; it was picking up a stale config.h from an
	overwritten installation.

get_config_h_filename, get_makefile_filename, parse_config_h, and
parse_makefile.