I don't know why zope.testrunner quits after the first layer.  I don't
want to know.  Let's try running tests exactly the same way as tox.ini.

Prevent contention when parallel tests are running under tox.

UnicodeDecodeError with bushy blob layout and non-ASCII OID

Fix a UnicodeDecodeError that could happen with blobs when the OID contained non-ascii bytes if ascii was the default encoding; test this.

Windows doesn't allow proper function with NamedTemporaryFile held open.

Another step toward PyPy support.

A step toward PyPy support.

Re-order changelog entries for 4.0.0b1.

Use the buildout to run these tests.

Try to work around zc.buildout's ignorance of setup_requires.

(I wish we had some real Windows developers who cared.  A 24-hour test
cycle is not exactly optimal.)

Improve logging of issue around blob

The guide package is `zodbdocs`.