attributes, etc. Biggest change was to the Distribution constructor
-- it now looks for an 'options' attribute, which contains values
(options) that are explicitly farmed out to the commands. Also,
certain options supplied to Distribution (ie. in the 'setup()' call in
setup.py) are now "command option aliases", meaning they are dropped
right into a certain command rather than being distribution options.
This is handled by a new Distribution class attribute,
'alias_options'.
Various comment changes to reflect the new way-of-thinking.
Added 'get_command_name()' method to Command -- was assuming its
existence all along as 'command_name()', so changed the code that
needs it to call 'get_command_name()'.
'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.
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.
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).