Added support for offline mode.

Used new API for test server management

Added an api for registering tearDown handlers.

Renamed distribution option to eggs and filled out README.txt.

The cheeseshop is too brittle.

The cheeseshop is too brittle.

The cheeseshop is too brittle.

Now the test namespace has a helper for creating temporary directories
that are automatically cleaned up.

the path set to include a set of distributions and their
dependeoncies. Now, you can also pass a script and arguments.  This
gives me a handy way of invoking setup.py scripts that require
setuptools without having to install setuptools into my system
python. :)

Reformated the tests to simplify the examples of calling the buildout
script.

distributions available. This required working around issues with
easy_install's --upgrade option:

- Upgrade is not recursive. Upgrading a distro doesn't update it's
  dependencies.

- Upgrade doesn't try very hard to avoid searching.  If we require a
  specific version of a distribution, and we already have that
  distribution, there's no point in looking for a newer one.

- easy_install has kind of odd rules for deciding when to look at an
  index.   Now that we use upgrade all the time, easy_install always
  wants to look at an index.

- We get warnings when connecting to index servers, like PyPI that 
  return text/plain not found messages.

We now have much greater control over how dependencies are
managed. We've essentially taken this over from easy_install.

Because we now always talk to an index server and because we want to
control anything we do in a test, many of the tests actually run their
own web servers.

Anyway:

- Now handle upgrades correctly, I think.

- The egg recipe can now install multiple distributions.

- We have the beginnings of offline mode.

- The internal architeture is much cleaner.

- We've merged the easy_install and egglinker modules, tossing
  some superfluois apis in the egglinker module.