[Boost-build] --help changes

From: Vladimir Prus (ghost_at_[hidden])
Date: 2007-01-06 14:20:47

Hi,
some time ago, in

        http://thread.gmane.org/gmane.comp.lib.boost.build/9365/

we've discussed how to improve the --help output. I think we've reached
an agreement, but nothing was implemented.

I've just committed the attached, that moves us close to the ideal.
I also attach two example output -- for boost and for example/hello.
In the latter case, there's some bogus project help printed, but otherwise
everything seems good to me.

I've renamed --help-all to --help-internal per the above discussion.

- Volodya