celery: drop traces of support for task_always_eager It was broken - retrieval of results didn't work. Also, task_always_eager still require a working celery.broker_url even though it is unused. It is thus much better to just set use_celery=false .

# requirements.txt file for use as "pip install -r requirements.txt" as a
# readthedocs compatible alternative to "pip install -e ." which is a working
# alternative to "setup.py develop" which doesn't work with Mercurial 3.7
.