Remove the obsolete Area model
Major changes in migrations:

- A project is split up in one or more 'Activities', those have
  scheduled measurements, organizations that do the work, measurement
  types

- The Contractor table was removed, in favor of using foreignkeys to
  Organization and/or Project or Activity.

- AvailableMeasurementTypes don't use a MeasurementType intermediate
  table anymore.

This breaks lots of code.
Model changes, first work on getting site back to work
Remove obsolete models from admin
Remove wizards, comparison view
Only have one contractor / measurementtype per organization
Get home page to work
Some fixes for the move from contractor to activity
Don't run migrations while testing, problems with ordering
Remove obsolete factories, switch to using SubFactory
Fix setting an activity's contractor
Reworking layers
Remove unused function
Move function to retrieve configuration option here
Remove unused code
Fixing tests
Fix uploaded file directory
Remove redundant measurementtype/organization fields from scheduledmeasurement
Connect Measurements directly to Locations
Move data to new structure