Load configuration once to avoid excessive IO about june HOT 2 CLOSED

I don't think there is a problem to have a default.py with all the defaults - but then the code should just not complain if it doesn't see a config file.  what I think what i mean is that our code should run without config files which may be missing.  if data files (like the company ones) are missing, then we just cannot run companies, this should go down to: if there are no data files at all, we make a box with 1000 people by default .... The individual problems I see are that: - data files are missing which prevents world.py from opening - the box_mode of world is not good enough - I assume we want to use it to test super-simple interaction models.  But then we need to make sure that our infection models can work - so, I don't mind stuffing lots of people into a box, but they must have all the characteristics of people (not groups), i.e. age, gender, health_index to allow for testing all aspects of infection. - we need to figure out how people like me can add stuff in a simple way.  One thing I found irritating today is that github is functionally a bit silly, compared to gitlab (which is what i usually use).  if you open an issue/ticket, gitlab allows you to directly create a branch to work on it ... i haven't seen this functionality on github but was looking.  so i hand-waved some feature_.... branch because I didn't see how to make a feature/... branch in an easy way. - it would be great to make a "stuff 1000 people in a box and look at how infection progresses" test for people to just blindly copy and test further features.  I wouldn't mind to have this in maximal simple form, with if __init__==__main__ or so.

-- ============================================ Professor Frank Krauss Royal Society Wolfson Fellow Institute for Particle Physics Phenomenology Director, Institute for Data Science Durham University Durham DH1 3LE United Kingdom Tel: +44 191 3343751 https://www.ippp.dur.ac.uk/profile/krauss ============================================