setuptools for mercurial-0.9.5

[Bryan O'Sullivan]

Matt Mackall wrote:

> I don't remember seeing your patch the first time around, but I'm not
> against the idea.

There's a severe problem with setuptools for developers, namely that it 
forcibly prepends the path to a package onto the front of sys.path in a 
way that cannot be overridden.  This makes it impossible to have two 
versions of a package installed simultaneously in different locations. 
This is a piece of design for which I have a hard time finding polite words.

I don't care if people want to screw up their systems that way, but it 
must not be the default behaviour of Mercurial's setup.py, or we won't 
even be able to run unit tests.

	<b