Our setup.cfg ensures that 'setup.py update_version' happens early
enough. And doing it from tox's commands= is too late anyways (because
we aren't using Versioneer, so the _version.py file must be updated
before tox installs a static copy into the virtualenv).
The buildbot's main run-trial-with-tox command has been updated to scan
for the 'tahoe --version' output and include the version string in the
buildbot results.
So use 'tox -e check-memory' instead of 'make check-memory'. The tox
version will create a virtualenv and install tahoe for you before
running the tests, removing one use of the 'tahoe @FILENAME' hack (which
was used to run a python file with a PYTHONPATH set to import tahoe's
dependencies).
This adds support for two environments: 'py27' for basic tests, and
'deprecations' to run tests with deprecation warnings turned on (the
latter is meant to be run from a buildbot step that knows how to count
and format the warnings nicely).
