- DistutilsOptionError is now documented as it's actually used, ie.
to indicate bogus option values (usually user options, eg. from
the command-line)
- added DistutilsSetupError to indicate errors that definitely arise
in the setup script
- got rid of DistutilsValueError, and changed all usage of it to
either DistutilsSetupError or ValueError as appropriate
- simplified a bunch of option get/set methods in Command and
Distribution classes -- just pass on AttributeError most of
the time, rather than turning it into something else
Greg Ward