Simpler out-of-the-box support for background updates. Now by default Celery uses an SQLite broker, with storage in the `.wiki` directory. This makes it possible to support async updates by simply passing `--usetasks` to `wk runserver`, while also running `wk runtasks` in a different process.

[pytest]
norecursedirs = .* _darcs CVS .svn .git .hg *.egg-info dist node_modules venv tmp* {args}