Booting up 0.9.4

[Clint Olsen]

Not to sound ungrateful for Mercurial, but this install thing is getting
irritating.  I really wish the methods for getting the Mercurial runtime
working would stop changing.

I used to have to set PYTHONPATH to some location in my installation area.
Now it appears Mercurial scribbles in some Python version-specific area
instead of just '...lib/python'.  I noticed that PYTHONPATH is not
documented in the root area in the installation, but if it set it to NULL
(but it must be set), hg figures out where it's marbles are and runs.

And while you're at it, can we do away with environment variable presets in
order to get Mercurial running?  That's what wrapper scripts are for.  And
since hg doesn't do much of anything other than import the entire class of
Mercurial, it seems logical to put that kind of stuff there.

Thanks,

-Clint