Remove unnecessary internal functions, also simple algebra
Move calculations out of tasks.py into calc.py, so that only task-related stuff is in tasks.py
Move main damage scenario calculate function into DamageScenario model
If we send all mails as user 'mail', and pass a logger to calculate, then calculate needs to know nothing about users, loglevels and tasks
Remove strange call_calc_damage_for_waterlevel function
Move gigantic calc_damage_for_waterlevel function into DamageEvent
Remove all the unnecessary arguments from damage event's calculate function; prevent circular imports; few other fixes after testing
Try to remove dependency on models (either a module imports models, or models import the module, not both).
Add and promote logging for indirect road damage.
Fix moved variable
Add scenario slug to info