Merged -r108904:HEAD

svn+ssh://svn.zope.org/repos/main/zc.buildout/branches/gary-1

Lots of good cleanup changes, including making windows tests a bit
more robust.


git-svn-id: http://svn.zope.org/repos/main/zc.buildout/trunk@109502 62d5b8a3-27da-0310-9561-8e5933582275