Update changelog
Bumped to 4.0 in preparation for next release.
Added tag 4.0 for changeset 63743681d5bb
Bumped to 4.1 in preparation for next release.
fix issue202 - update existing zipimporters when replacing a zipped egg

When replacing a zipped egg distribution with a different zipped egg, we make
all existing zipimport.zipimporter loaders valid again instead of having to go
hunting them down one by one. This is done by updating their shared zip
directory information cache - zipimport._zip_directory_cache.

Related to the following project issues:
  #169 - http://bitbucket.org/pypa/setuptools/issue/168
  #202 - http://bitbucket.org/pypa/setuptools/issue/202

--HG--
extra : rebase_source : df4e3a53e307481be584f9e956e4c628dbec162b
remove quick-fix comment for the solution to issue #169.

Although the original problematic use case when we are replacing a zipped egg
distribution with another zipped egg distribution is now cleanly handled by
fixing all existing zipimport.zipimporter loaders, this fix is still valid for
cases when replacing a distribution with a non-zipped egg folder.

--HG--
extra : rebase_source : 98796ffcc43560bb32ff0b2f478e3efc67a4d6b2